diff --git a/README.md b/README.md
index d0de0e2..26602ff 100644
--- a/README.md
+++ b/README.md
@@ -19,11 +19,16 @@ Some sample features:
 Free tier does not support Queuemail professional SMTP servers. So you must to configure [free SMTP servers](other-freesmtps.md) or your custom SMTP server.
 
 
+#### CLIENTS:
 
-### CLIENTS AND EXAMPLES:
+* [queuemail-client: A basic Java client to use QUEUEMAIL.DEV API](https://github.com/queuemail/docs-and-examples/tree/main/queuemail-client).
 
-* [queuemail-client: A basic Java client to use QUEUEMAIL.DEV API](https://github.com/queuemail/docs-and-examples/tree/main/queuemail-client)
+#### EXAMPLES:
+
+* [Hardy Client: A robust Java client to use QUEUEMAIL.DEV API](examples-hardyservice.md).
 
 
 ### CHANGELOG:
-* **2023-07-18**: Added **sendate** parameter to [sending emails endpoint](api-emails.md) in order to schedule emails to send.
\ No newline at end of file
+* **2023-07-18**: Added **sendate** parameter to [sending emails endpoint](api-emails.md) in order to schedule emails to send.
+
+* **2023-07-21**: Added example: [Hardy Client: A robust Java client to use QUEUEMAIL.DEV API](examples-hardyservice.md).
diff --git a/es/README.md b/es/README.md
index 8dad05c..3402cf4 100644
--- a/es/README.md
+++ b/es/README.md
@@ -20,10 +20,17 @@ La capa gratuita no incluye el uso de los servidores SMTP profesionales de Queue
 
 
 
-### CLIENTES Y EJEMPLOS:
+### CLIENTES:
+
+* [queuemail-client: Cliente básico en Java para usar la API de QUEUEMAIL.DEV](https://github.com/queuemail/docs-and-examples/tree/main/queuemail-client).
+
+### EJEMPLOS:
+
+* [Hardy Client: Un cliente en Java robusto para usar QUEUEMAIL.DEV API](examples-hardyservice.md).
 
-* [queuemail-client: Cliente básico en Java para usar la API de QUEUEMAIL.DEV](https://github.com/queuemail/docs-and-examples/tree/main/queuemail-client)
 
 ### REGISTRO DE CAMBIOS:
 
-* **2023-07-18**: Se añade el parámetro **sendate** a la llamada para [enviar emails](api-emails.md) que permite programar envíos en el futuro.
\ No newline at end of file
+* **2023-07-18**: Se añade el parámetro **sendate** a la llamada para [enviar emails](api-emails.md) que permite programar envíos en el futuro.
+
+* **2023-07-21**: Añadido el ejemplo: [Hardy Client: Un cliente en Java robusto para usar QUEUEMAIL.DEV API](examples-hardyservice.md).
diff --git a/es/examples-hardyservice.md b/es/examples-hardyservice.md
new file mode 100644
index 0000000..47c9afd
--- /dev/null
+++ b/es/examples-hardyservice.md
@@ -0,0 +1,1246 @@
+
+### Hardy Client: Un cliente en Java robusto para usar QUEUEMAIL.DEV API
+
+¿Qué sucede si hay cortes de red o caída del servidor mientras se usa la la API de QUEUEMAIL.DEV?
+
+La solución es implementar una cola loca para almacenar los emails que fallan cuando QUEUEMAIL no responde.
+
+Para este ejemplo vamos a usar un proyecto Spring Boot similar a [queuemail-client: A basic Java client to use QUEUEMAIL.DEV API](https://github.com/queuemail/docs-and-examples/tree/main/queuemail-client) y estableceremos las siguientes propiedades en el fichero *application.properties*:
+
+```
+queuemail.username=******
+queuemail.password=******
+queuemail.idapp=******
+
+```
+
+Los valores de esas propiedades son el nombre de usuario y contraseña de tu cuenta QUEUEMAIL.DEV y el id de la app que vayas a usar. Puedes crear tu app con el [endpoint de apps](api-apps.md).
+
+Ahora, vamos a usar los siguientes DTO's:
+
+LogDTO.java:
+
+```
+package miapp.queuemail.dto;
+
+
+import java.time.LocalDateTime;
+
+public class LogDTO
+{
+    private String to;
+    private String resultcode;
+    private LocalDateTime when;
+
+    private String _id;
+
+    private String idsending;
+
+    private String idsmtp;
+
+    private String idapp;
+
+    private LocalDateTime created;
+
+    public String getTo() {
+        return to;
+    }
+
+    public void setTo(String to) {
+        this.to = to;
+    }
+
+    public String getResultcode() {
+        return resultcode;
+    }
+
+    public void setResultcode(String resultcode) {
+        this.resultcode = resultcode;
+    }
+
+    public LocalDateTime getWhen() {
+        return when;
+    }
+
+    public void setWhen(LocalDateTime when) {
+        this.when = when;
+    }
+
+    public String get_id() {
+        return _id;
+    }
+
+    public void set_id(String _id) {
+        this._id = _id;
+    }
+
+    public String getIdsending() {
+        return idsending;
+    }
+
+    public void setIdsending(String idsending) {
+        this.idsending = idsending;
+    }
+
+    public String getIdsmtp() {
+        return idsmtp;
+    }
+
+    public void setIdsmtp(String idsmtp) {
+        this.idsmtp = idsmtp;
+    }
+
+    public String getIdapp() {
+        return idapp;
+    }
+
+    public void setIdapp(String idapp) {
+        this.idapp = idapp;
+    }
+
+    public LocalDateTime getCreated() {
+        return created;
+    }
+
+    public void setCreated(LocalDateTime created) {
+        this.created = created;
+    }
+}
+
+```
+
+LoginResponseDTO.java:
+
+```
+package miapp.queuemail.dto;
+
+public class LoginResponseDTO
+{
+
+    private String token;
+    private String role;
+    private String userId;
+    private String username;
+    private String clientId;
+
+    public String getToken() {
+        return token;
+    }
+
+    public void setToken(String token) {
+        this.token = token;
+    }
+
+    public String getRole() {
+        return role;
+    }
+
+    public void setRole(String role) {
+        this.role = role;
+    }
+
+    public String getUserId() {
+        return userId;
+    }
+
+    public void setUserId(String userId) {
+        this.userId = userId;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getClientId() {
+        return clientId;
+    }
+
+    public void setClientId(String clientId) {
+        this.clientId = clientId;
+    }
+
+}
+
+```
+
+SendingResultDTO.java:
+```
+package miapp.queuemail.dto;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+@JsonInclude(JsonInclude.Include.NON_NULL)
+public class SendingResultDTO
+{
+    String id;
+    String status;
+    LocalDateTime inittime;
+    LocalDateTime logsdeleledby;
+    List<String> attachments;
+
+
+    List<String> blacklisted;
+    List<String> autoblacklisted;
+    List<String> notvalidrecipients;
+
+    List<LogDTO> log;
+    List<TrackingDTO> opened;
+    LocalDateTime finishtime;
+
+    String error;
+    Boolean localqueued;
+
+    public SendingResultDTO() {
+        super();
+    }
+
+    public SendingResultDTO(String id, String status, LocalDateTime inittime, LocalDateTime logsdeleledby, List<String> attachments, List<String> blacklisted, List<String> autoblacklisted, List<String> notvalidrecipients, List<LogDTO> log, List<TrackingDTO> opened, LocalDateTime finishtime, String error) {
+        this.id = id;
+        this.status = status;
+        this.inittime = inittime;
+        this.logsdeleledby = logsdeleledby;
+        this.attachments = attachments;
+        this.blacklisted = blacklisted;
+        this.autoblacklisted = autoblacklisted;
+        this.notvalidrecipients = notvalidrecipients;
+        this.log = log;
+        this.opened = opened;
+        this.finishtime = finishtime;
+        this.error = error;
+        this.localqueued = false;
+    }
+
+    public SendingResultDTO(String error)
+    {
+        this.error = error;
+        this.localqueued = false;
+    }
+
+    public SendingResultDTO(String error, Boolean localqueued)
+    {
+        this.error = error;
+        this.localqueued = localqueued;
+    }
+
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public List<String> getBlacklisted() {
+        return blacklisted;
+    }
+
+    public void setBlacklisted(List<String> blacklisted) {
+        this.blacklisted = blacklisted;
+    }
+
+    public List<String> getAutoblacklisted() {
+        return autoblacklisted;
+    }
+
+    public void setAutoblacklisted(List<String> autoblacklisted) {
+        this.autoblacklisted = autoblacklisted;
+    }
+
+    public List<String> getAttachments() {
+        return attachments;
+    }
+
+    public String getStatus() {
+        return status;
+    }
+
+    public void setStatus(String status) {
+        this.status = status;
+    }
+
+    public LocalDateTime getInittime() {
+        return inittime;
+    }
+
+    public void setInittime(LocalDateTime inittime) {
+        this.inittime = inittime;
+    }
+
+    public List<LogDTO> getLog() {
+        return log;
+    }
+
+    public void setLog(List<LogDTO> log) {
+        this.log = log;
+    }
+
+    public List<TrackingDTO> getOpened() {
+        return opened;
+    }
+
+    public void setOpened(List<TrackingDTO> opened) {
+        this.opened = opened;
+    }
+
+    public LocalDateTime getFinishtime() {
+        return finishtime;
+    }
+
+    public void setFinishtime(LocalDateTime finishtime) {
+        this.finishtime = finishtime;
+    }
+
+    public void setAttachments(List<String> attachments) {
+        this.attachments = attachments;
+    }
+
+    public List<String> getNotvalidrecipients() {
+        return notvalidrecipients;
+    }
+
+    public void setNotvalidrecipients(List<String> notvalidrecipients) {
+        this.notvalidrecipients = notvalidrecipients;
+    }
+
+    public String getError() {
+        return error;
+    }
+
+    public void setError(String error) {
+        this.error = error;
+    }
+
+    public LocalDateTime getLogsdeleledby() {
+        return logsdeleledby;
+    }
+
+    public void setLogsdeleledby(LocalDateTime logsdeleledby) {
+        this.logsdeleledby = logsdeleledby;
+    }
+
+    public Boolean getLocalqueued() {
+        return localqueued;
+    }
+
+    public void setLocalqueued(Boolean localqueued) {
+        this.localqueued = localqueued;
+    }
+
+}
+
+```
+
+TrackingDTO.java:
+```
+package miapp.queuemail.dto;
+
+
+import java.time.LocalDateTime;
+
+public class TrackingDTO
+{
+    private String email;
+    private LocalDateTime when;
+
+    private String _id;
+
+    private String idsending;
+
+    private String idmailing;
+
+    private String type; //OPEN, CLICK
+
+    private String url;
+
+    private LocalDateTime created;
+
+    private String ip;
+
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public LocalDateTime getWhen() {
+        return when;
+    }
+
+    public void setWhen(LocalDateTime when) {
+        this.when = when;
+    }
+
+    public String get_id() {
+        return _id;
+    }
+
+    public void set_id(String _id) {
+        this._id = _id;
+    }
+
+    public String getIdsending() {
+        return idsending;
+    }
+
+    public void setIdsending(String idsending) {
+        this.idsending = idsending;
+    }
+
+    public String getIdmailing() {
+        return idmailing;
+    }
+
+    public void setIdmailing(String idmailing) {
+        this.idmailing = idmailing;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public String getUrl() {
+        return url;
+    }
+
+    public void setUrl(String url) {
+        this.url = url;
+    }
+
+    public LocalDateTime getCreated() {
+        return created;
+    }
+
+    public void setCreated(LocalDateTime created) {
+        this.created = created;
+    }
+
+    public String getIp() {
+        return ip;
+    }
+
+    public void setIp(String ip) {
+        this.ip = ip;
+    }
+}
+
+```
+Ahora, vamos a definir dos entidades para almacenar los emails fallidos en una cola local:
+
+QueueEmail.java:
+```
+package miapp.queuemail.model;
+
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+@Document(collection = "queuemails")
+public class QueueEmail
+{
+    @Id
+    private String _id;
+
+    private String idapp;
+
+    private String idmailing;
+
+    private String from;
+
+    private String fromname;
+
+    private String to;
+
+    private String toname;
+
+    private String ccs;
+
+    private String bccs;
+
+    private String replyto;
+
+    private String subject;
+
+    private String subjectencoding;
+
+    private String body;
+
+    private String bodyencoding;
+
+    private String mimetype;
+
+    private String attachmentstype;
+
+    private List<String> urlattachments;
+
+    private Boolean includetracking;
+
+    private Boolean includeUnregisterLink;
+
+    private LocalDateTime senddate;
+
+    private Integer numretries;
+
+    private LocalDateTime created;
+
+    private LocalDateTime modified;
+
+
+    public QueueEmail()
+    {
+        this.numretries = 0;
+        this.created = this.modified = LocalDateTime.now();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        QueueEmail that = (QueueEmail) o;
+
+        return _id.equals(that._id);
+    }
+
+    @Override
+    public int hashCode() {
+        return _id.hashCode();
+    }
+
+    public String get_id() {
+        return _id;
+    }
+
+    public void set_id(String _id) {
+        this._id = _id;
+    }
+
+    public String getIdapp() {
+        return idapp;
+    }
+
+    public void setIdapp(String idapp) {
+        this.idapp = idapp;
+    }
+
+    public String getIdmailing() {
+        return idmailing;
+    }
+
+    public void setIdmailing(String idmailing) {
+        this.idmailing = idmailing;
+    }
+
+    public String getFrom() {
+        return from;
+    }
+
+    public void setFrom(String from) {
+        this.from = from;
+    }
+
+    public String getFromname() {
+        return fromname;
+    }
+
+    public void setFromname(String fromname) {
+        this.fromname = fromname;
+    }
+
+    public String getTo() {
+        return to;
+    }
+
+    public void setTo(String to) {
+        this.to = to;
+    }
+
+    public String getToname() {
+        return toname;
+    }
+
+    public void setToname(String toname) {
+        this.toname = toname;
+    }
+
+    public String getCcs() {
+        return ccs;
+    }
+
+    public void setCcs(String ccs) {
+        this.ccs = ccs;
+    }
+
+    public String getBccs() {
+        return bccs;
+    }
+
+    public void setBccs(String bccs) {
+        this.bccs = bccs;
+    }
+
+    public String getReplyto() {
+        return replyto;
+    }
+
+    public void setReplyto(String replyto) {
+        this.replyto = replyto;
+    }
+
+    public String getSubject() {
+        return subject;
+    }
+
+    public void setSubject(String subject) {
+        this.subject = subject;
+    }
+
+    public String getSubjectencoding() {
+        return subjectencoding;
+    }
+
+    public void setSubjectencoding(String subjectencoding) {
+        this.subjectencoding = subjectencoding;
+    }
+
+    public String getBody() {
+        return body;
+    }
+
+    public void setBody(String body) {
+        this.body = body;
+    }
+
+    public String getBodyencoding() {
+        return bodyencoding;
+    }
+
+    public void setBodyencoding(String bodyencoding) {
+        this.bodyencoding = bodyencoding;
+    }
+
+    public String getMimetype() {
+        return mimetype;
+    }
+
+    public void setMimetype(String mimetype) {
+        this.mimetype = mimetype;
+    }
+
+    public String getAttachmentstype() {
+        return attachmentstype;
+    }
+
+    public void setAttachmentstype(String attachmentstype) {
+        this.attachmentstype = attachmentstype;
+    }
+
+    public Boolean getIncludetracking() {
+        return includetracking;
+    }
+
+    public void setIncludetracking(Boolean includetracking) {
+        this.includetracking = includetracking;
+    }
+
+    public Boolean getIncludeUnregisterLink() {
+        return includeUnregisterLink;
+    }
+
+    public void setIncludeUnregisterLink(Boolean includeUnregisterLink) {
+        this.includeUnregisterLink = includeUnregisterLink;
+    }
+
+    public LocalDateTime getSenddate() {
+        return senddate;
+    }
+
+    public void setSenddate(LocalDateTime senddate) {
+        this.senddate = senddate;
+    }
+
+    public Integer getNumretries() {
+        return numretries;
+    }
+
+    public void setNumretries(Integer numretries) {
+        this.numretries = numretries;
+    }
+
+    public LocalDateTime getCreated() {
+        return created;
+    }
+
+    public void setCreated(LocalDateTime created) {
+        this.created = created;
+    }
+
+    public LocalDateTime getModified() {
+        return modified;
+    }
+
+    public void setModified(LocalDateTime modified) {
+        this.modified = modified;
+    }
+
+    public List<String> getUrlattachments() {
+        return urlattachments;
+    }
+
+    public void setUrlattachments(List<String> urlattachments) {
+        this.urlattachments = urlattachments;
+    }
+}
+```
+
+QueueEmailAttachment.java:
+```
+package miapp.queuemail.model;
+
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+@Document(collection = "queuemails_attachments")
+public class QueueEmailAttachment
+{
+    @Id
+    private String _id;
+
+    private String idemail;
+
+    private String filepath;
+
+    private Boolean removeAfterSent;
+
+
+    public QueueEmailAttachment()
+    {
+        this.removeAfterSent = false;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        QueueEmailAttachment that = (QueueEmailAttachment) o;
+
+        return _id.equals(that._id);
+    }
+
+    @Override
+    public int hashCode() {
+        return _id.hashCode();
+    }
+
+
+    public String get_id() {
+        return _id;
+    }
+
+    public void set_id(String _id) {
+        this._id = _id;
+    }
+
+    public String getIdemail() {
+        return idemail;
+    }
+
+    public void setIdemail(String idemail) {
+        this.idemail = idemail;
+    }
+
+    public String getFilepath() {
+        return filepath;
+    }
+
+    public void setFilepath(String filepath) {
+        this.filepath = filepath;
+    }
+
+    public Boolean getRemoveAfterSent() {
+        return removeAfterSent;
+    }
+
+    public void setRemoveAfterSent(Boolean removeAfterSent) {
+        this.removeAfterSent = removeAfterSent;
+    }
+}
+```
+
+Now, we are going to define repositories for these entities:
+
+QueueEmailsRepository.java:
+```
+package miapp.queuemail.repositories;
+
+import miapp.queuemail.model.QueueEmail;
+import org.springframework.data.mongodb.repository.MongoRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+
+@Repository
+public interface QueueEmailsRepository extends MongoRepository<QueueEmail, String>
+{
+
+	List<QueueEmail> findAll();
+}
+```
+
+QueueEmailAttachmentsRepository.java:
+```
+package miapp.queuemail.repositories;
+
+import miapp.queuemail.model.QueueEmailAttachment;
+import org.springframework.data.mongodb.repository.MongoRepository;
+import org.springframework.data.mongodb.repository.Query;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+@Repository
+public interface QueueEmailAttachmentsRepository extends MongoRepository<QueueEmailAttachment, String>
+{
+
+	@Query("{ 'idemail' : ?0 }")
+	List<QueueEmailAttachment> findByEmail(String idemail);
+
+	@Query(value="{'idemail' : ?0}", delete = true)
+	public void deleteByEmail(String idemail);
+}
+
+```
+Ahora, vamos a definir el servicio con tan solo dos operaciones de API (login y envío de emails) y un método programado periódicamente para procesar nuestra cola local:
+
+QueuemailHardyService.java:
+
+```
+package miapp.queuemail.dev.service;
+
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import miapp.queuemail.repositories.QueueEmailAttachmentsRepository;
+import miapp.queuemail.repositories.QueueEmailsRepository;
+import miapp.queuemail.model.QueueEmail;
+import miapp.queuemail.model.QueueEmailAttachment;
+import miapp.queuemail.dto.LoginResponseDTO;
+import miapp.queuemail.dto.SendingResultDTO;
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.fluent.Form;
+import org.apache.http.client.fluent.Request;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.entity.ContentType;
+import org.apache.http.entity.mime.MultipartEntityBuilder;
+import org.apache.http.entity.mime.content.FileBody;
+import org.apache.http.entity.mime.content.StringBody;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Service;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.InputStreamReader;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.List;
+
+
+
+@Service
+public class QueuemailHardyService
+{
+    private static final String API_MAIN_URL = "https://api.queuemail.dev/api";
+
+    @Value("${queuemail.username}")
+    private String username;
+
+    @Value("${queuemail.password}")
+    private String password;
+
+    @Value("${queuemail.idapp}")
+    private String idapp;
+
+    final QueueEmailsRepository queueEmailsRepository;
+    final QueueEmailAttachmentsRepository queueEmailAttachmentsRepository;
+
+    public QueuemailHardyService(QueueEmailsRepository queueEmailsRepository, QueueEmailAttachmentsRepository queueEmailAttachmentsRepository)
+    {
+        this.queueEmailsRepository = queueEmailsRepository;
+        this.queueEmailAttachmentsRepository = queueEmailAttachmentsRepository;
+    }
+
+
+    public LoginResponseDTO login() throws Exception
+    {
+        try
+        {
+            HttpResponse response = Request.Post(API_MAIN_URL + "/auth/login").bodyForm(Form.form()
+                    .add("username", username)
+                    .add("password", password)
+                    .build()).execute().returnResponse();
+
+            if (response.getStatusLine().getStatusCode() == 200)
+            {
+                ObjectMapper mapper = new ObjectMapper();
+                mapper.enable(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);
+                mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+                LoginResponseDTO res =  mapper.readValue(response.getEntity().getContent(), LoginResponseDTO.class);
+                return res;
+            }
+            else if (response.getStatusLine().getStatusCode() == 403)
+            {
+                throw new Exception("USER_PASSWORD_NOT_VALID");
+            }
+            else
+            {
+                throw new Exception("ERROR_LOGIN");
+            }
+        }
+        catch(Exception e)
+        {
+            e.printStackTrace();
+            throw new Exception("GENERAL_ERROR");
+        }
+    }
+
+    public SendingResultDTO sendEmail(String token,
+                                      String from, String fromname, String to, String toname,
+                                      String ccs, String bccs, String replyto,
+                                      String subject, String subjectencoding, String body, String bodyencoding,
+                                      String mimetype,
+                                      List<File> attachments,
+                                      List<String> urlattachments,
+                                      String attachmenttype,
+                                      Boolean includetracking,
+                                      Boolean includeunregisterlink,
+                                      Boolean localqueue,
+                                      Boolean removeAttachmentsAfterSent)
+    {
+        try
+        {
+            final SendingResultDTO[] res = new SendingResultDTO[1];
+
+            if(token==null) token = this.login().getToken();
+            if(token==null)
+            {
+                return new SendingResultDTO("AUTH_ERROR",
+                        this.queueEmail(idapp,
+                                from, fromname, to, toname,
+                                ccs, bccs, replyto,
+                                subject, subjectencoding, body, bodyencoding,
+                                mimetype,
+                                attachments,
+                                urlattachments,
+                                attachmenttype,
+                                includetracking,
+                                includeunregisterlink,
+                                localqueue,
+                                removeAttachmentsAfterSent));
+            }
+
+            HttpPost httppost = new HttpPost(API_MAIN_URL + "/private/emails/send");
+            httppost.addHeader("Authorization", "Bearer " + token);
+
+            MultipartEntityBuilder mpeb = MultipartEntityBuilder.create();
+
+            if(attachments!=null && attachments.size()>0)
+                for(File mf : attachments)
+                {
+                    mpeb.addPart("attachments", new FileBody(mf));
+                }
+
+            mpeb.addPart("idapp", new StringBody(idapp, ContentType.TEXT_PLAIN));
+            if(from!=null) mpeb.addPart("from", new StringBody(from, ContentType.TEXT_PLAIN));
+            if(fromname!=null) mpeb.addPart("fromname", new StringBody(fromname, ContentType.TEXT_PLAIN));
+            if(to!=null) mpeb.addPart("tos", new StringBody(to, ContentType.TEXT_PLAIN));
+            if(toname!=null) mpeb.addPart("tonames", new StringBody(toname, ContentType.TEXT_PLAIN));
+            if(ccs!=null) mpeb.addPart("ccs", new StringBody(ccs, ContentType.TEXT_PLAIN));
+            if(bccs!=null) mpeb.addPart("bccs", new StringBody(bccs, ContentType.TEXT_PLAIN));
+            if(replyto!=null) mpeb.addPart("replyto", new StringBody(replyto, ContentType.TEXT_PLAIN));
+            if(subject!=null) mpeb.addPart("subject", new StringBody(subject, ContentType.TEXT_PLAIN));
+            if(subjectencoding!=null) mpeb.addPart("subjectencoding", new StringBody(subjectencoding, ContentType.TEXT_PLAIN));
+            if(body!=null) mpeb.addPart("body", new StringBody(body, ContentType.TEXT_PLAIN));
+            if(bodyencoding!=null) mpeb.addPart("bodyencoding", new StringBody(bodyencoding, ContentType.TEXT_PLAIN));
+            if(mimetype!=null) mpeb.addPart("mimetype", new StringBody(mimetype, ContentType.TEXT_PLAIN));
+            if(attachmenttype!=null) mpeb.addPart("attachmenttype", new StringBody(attachmenttype, ContentType.TEXT_PLAIN));
+            if(urlattachments!=null) mpeb.addPart("urlattachments", new StringBody(String.join(",", urlattachments), ContentType.TEXT_PLAIN));
+            if(includetracking!=null) mpeb.addPart("includetracking", new StringBody(""+includetracking, ContentType.TEXT_PLAIN));
+            if(includeunregisterlink!=null) mpeb.addPart("includeunregisterlink", new StringBody(""+includeunregisterlink, ContentType.TEXT_PLAIN));
+
+            HttpEntity reqEntity = mpeb.build();
+            httppost.setEntity(reqEntity);
+
+            ObjectMapper mapper = new ObjectMapper();
+            mapper.enable(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);
+            mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+            mapper.registerModule(new JavaTimeModule());
+
+            try(CloseableHttpClient client = HttpClientBuilder.create().build())
+            {
+                client.execute(httppost, response -> {
+                    if (response.getStatusLine().getStatusCode() == 200)
+                    {
+                        if(removeAttachmentsAfterSent!=null && removeAttachmentsAfterSent==true)
+                            for(File file : attachments) try { file.delete(); } catch (Exception e) { e.printStackTrace();}
+
+                        res[0] = mapper.readValue(response.getEntity().getContent(), SendingResultDTO.class);
+                    }
+                    else if (response.getStatusLine().getStatusCode() == 401)
+                    {
+                        res[0] = new SendingResultDTO("Not authorized", false);
+                    }
+                    else if (response.getStatusLine().getStatusCode() == 403)
+                    {
+                        res[0] = new SendingResultDTO("Credentials not valid", false);
+                    }
+                    else if (response.getStatusLine().getStatusCode() == 406)
+                    {
+                        String responseString = "";
+                        BufferedReader br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
+                        String readLine;
+                        while (((readLine = br.readLine()) != null)) responseString += readLine;
+                        br.close();
+                        res[0] = new SendingResultDTO(responseString,
+                        this.queueEmail(idapp,
+                                from, fromname, to, toname,
+                                ccs, bccs, replyto,
+                                subject, subjectencoding, body, bodyencoding,
+                                mimetype,
+                                attachments,
+                                urlattachments,
+                                attachmenttype,
+                                includetracking,
+                                includeunregisterlink,
+                                localqueue==null?false:localqueue,
+                                removeAttachmentsAfterSent==null?false:removeAttachmentsAfterSent));
+                    }
+                    else
+                    {
+                        res[0] = new SendingResultDTO("ERROR_SENDING_EMAIL",
+                        this.queueEmail(idapp,
+                                from, fromname, to, toname,
+                                ccs, bccs, replyto,
+                                subject, subjectencoding, body, bodyencoding,
+                                mimetype,
+                                attachments,
+                                urlattachments,
+                                attachmenttype,
+                                includetracking,
+                                includeunregisterlink,
+                                localqueue==null?false:localqueue,
+                                removeAttachmentsAfterSent==null?false:removeAttachmentsAfterSent));
+                    }
+
+                    return res[0];
+                });
+
+
+            } catch (Exception e) { throw e; }
+
+            return res[0];
+        }
+        catch(Exception e)
+        {
+            e.printStackTrace();
+            return new SendingResultDTO("GENERAL_ERROR",
+                    this.queueEmail(idapp,
+                            from, fromname, to, toname,
+                            ccs, bccs, replyto,
+                            subject, subjectencoding, body, bodyencoding,
+                            mimetype,
+                            attachments,
+                            urlattachments,
+                            attachmenttype,
+                            includetracking,
+                            includeunregisterlink,
+                            localqueue==null?false:localqueue,
+                            removeAttachmentsAfterSent==null?false:removeAttachmentsAfterSent));
+        }
+    }
+
+
+    private boolean queueEmail(String idapp,
+                            String from, String fromname, String to, String toname,
+                            String ccs, String bccs, String replyto,
+                            String subject, String subjectencoding, String body, String bodyencoding,
+                            String mimetype,
+                            List<File> attachments,
+                            List<String> urlattachments,
+                            String attachmenttype,
+                            Boolean includetracking,
+                            Boolean includeunregisterlink,
+                            Boolean localqueue,
+                            Boolean removeAttachmentsAfterSent)
+    {
+        try
+        {
+            if(!localqueue) return  false;
+
+            QueueEmail queueEmail = new QueueEmail();
+            queueEmail.setIdapp(idapp);
+            queueEmail.setFrom(from);
+            queueEmail.setFromname(fromname);
+            queueEmail.setTo(to);
+            queueEmail.setToname(toname);
+            queueEmail.setCcs(ccs);
+            queueEmail.setBccs(bccs);
+            queueEmail.setReplyto(replyto);
+            queueEmail.setSubject(subject);
+            queueEmail.setSubjectencoding(subjectencoding);
+            queueEmail.setBody(body);
+            queueEmail.setBodyencoding(bodyencoding);
+            queueEmail.setMimetype(mimetype);
+            queueEmail.setUrlattachments(urlattachments);
+            queueEmail.setAttachmentstype(attachmenttype);
+            queueEmail.setIncludetracking(includetracking);
+            queueEmail.setIncludeUnregisterLink(includeunregisterlink);
+            queueEmail = this.queueEmailsRepository.save(queueEmail);
+
+            if (attachments != null && attachments.size() > 0)
+                for (File file : attachments) {
+                    QueueEmailAttachment queueEmailAttachment = new QueueEmailAttachment();
+                    queueEmailAttachment.setIdemail(queueEmail.get_id());
+                    queueEmailAttachment.setFilepath(file.getAbsolutePath());
+                    queueEmailAttachment.setRemoveAfterSent(removeAttachmentsAfterSent);
+                    this.queueEmailAttachmentsRepository.save(queueEmailAttachment);
+                }
+
+            return true;
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace();
+            return false;
+        }
+    }
+
+    @Scheduled(fixedRate = 1000*60*5) // 5 minutes
+    public void processQueuedEmails()
+    {
+        try
+        {
+            List<QueueEmail> pendingemails = this.queueEmailsRepository.findAll(); //TODO: improve sorting in order to better selection based on created or numretries
+            if(pendingemails==null || pendingemails.size()==0) return;
+
+            System.out.println("\n" + LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS")) + " - Procesing queued email.");
+
+            String token = this.login().getToken();
+            if(token==null) throw new Exception("NO VALID TOKEN");
+
+            for(QueueEmail queueEmail : pendingemails)
+            {
+                try
+                {
+                    List<File> attachments = null;
+                    List<QueueEmailAttachment> qattachments = this.queueEmailAttachmentsRepository.findByEmail(queueEmail.get_id());
+                    if(qattachments!=null && qattachments.size()>0)
+                    {
+                        attachments = new ArrayList<>(qattachments.size());
+                        for(QueueEmailAttachment queueEmailAttachment : qattachments)
+                            attachments.add(new File(queueEmailAttachment.getFilepath()));
+                    }
+
+                    SendingResultDTO sendingResultDTO = this.sendEmail(token,
+                            queueEmail.getFrom(), queueEmail.getFromname(),  queueEmail.getTo(), queueEmail.getToname(),
+                            queueEmail.getCcs(), queueEmail.getBccs(), queueEmail.getReplyto(),
+                            queueEmail.getSubject(), queueEmail.getSubjectencoding(), queueEmail.getBody(), queueEmail.getBodyencoding(),
+                            queueEmail.getMimetype(),
+                            attachments,
+                            queueEmail.getUrlattachments(),
+                            queueEmail.getAttachmentstype(),
+                            queueEmail.getIncludetracking(),
+                            queueEmail.getIncludeUnregisterLink(),
+                            false, //at queue process do not queue up again!
+                            null);
+
+                    if(sendingResultDTO==null || sendingResultDTO.getStatus()==null || sendingResultDTO.getError()!=null)
+                    {
+                        queueEmail.setNumretries(queueEmail.getNumretries()+1);
+                        queueEmail.setModified(LocalDateTime.now());
+                        this.queueEmailsRepository.save(queueEmail);
+                    }
+                    else
+                    {
+                        this.queueEmailsRepository.delete(queueEmail);
+                        try
+                        {
+                            if(qattachments!=null && qattachments.size()>0)
+                            {
+                                for(QueueEmailAttachment queueEmailAttachment : qattachments)
+                                   if(queueEmailAttachment.getRemoveAfterSent())
+                                       new File(queueEmailAttachment.getFilepath()).delete();
+                            }
+                        }
+                        catch (Exception e) { e.printStackTrace(); }
+                        this.queueEmailAttachmentsRepository.deleteByEmail(queueEmail.get_id());
+                    }
+                }
+                catch (Exception e)
+                {
+                    try { queueEmail.setNumretries(queueEmail.getNumretries()+1); queueEmail.setModified(LocalDateTime.now()); this.queueEmailsRepository.save(queueEmail); } catch (Exception ee) {}
+                    e.printStackTrace();
+                }
+            }
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace();
+        }
+    }
+
+}
+
+```
+
+En este momento ya tenemos todo el código necesario para reemplazar nuestra forma habitual de enviar emails:
+
+```
+SendEmail.send( fromemail, toemail, subject, body );
+````
+
+por otra nueva y más robusta:
+
+```
+        @Autowired
+        QueuemailHardyService queuemailHardyService;
+
+        [...]
+
+		SendingResultDTO sendingResultDTO = this.queuemailHardyService.sendEmail(null, fromemail, "Mi name",  toemail, "Your name", null, null, fromemail,
+				subject, "UTF-8", body, "UTF-8", "text/html",
+				null, null, null,
+				true, false,
+				true, null);
+
+		if(sendingResultDTO==null || (sendingResultDTO.getLocalqueued()!=null && sendingResultDTO.getLocalqueued()==false) )
+		{
+			SendEmail.send( fromemail, toemail, subject, body ); // we will send using usual way as failover
+		}
+```
+
+Puedes realizar más controles del estado del email, códigos de error, etc. También puedes controlar cuantas veces los emails se reintentan en la cola loca usando el campo *SendingResultDTO.numretries*.
+
+
diff --git a/es/other-faqs.md b/es/other-faqs.md
index b16fc67..4e62339 100644
--- a/es/other-faqs.md
+++ b/es/other-faqs.md
@@ -1,4 +1,12 @@
 
+
+### ¿Qué sucede si hay cortes de red o caída del servidor mientras se usa la la API de QUEUEMAIL.DEV?
+
+La solución es implementar una cola loca para almacenar los emails que fallan cuando QUEUEMAIL no responde.
+
+El ejemplo [Hardy client](examples-hardyservice.md) muestra como implementar esta cola local.
+
+
 ### Puedo enviar emails usando direcciones de mi propio dominio?
 
 
diff --git a/examples-hardyservice.md b/examples-hardyservice.md
new file mode 100644
index 0000000..e4c9d49
--- /dev/null
+++ b/examples-hardyservice.md
@@ -0,0 +1,1247 @@
+
+### Hardy Client: A robust Java client to use QUEUEMAIL.DEV API
+
+What happens if there are network outages or server downtime while calling QUEUEMAIL.DEV API?
+
+The solution is to implement a local queue to store failed emails when QUEUEMAIL.DEV does not respond.
+
+For this example we will use a Spring Boot project similar to [queuemail-client: A basic Java client to use QUEUEMAIL.DEV API](https://github.com/queuemail/docs-and-examples/tree/main/queuemail-client) and we set the following properties at *application.properties* file:
+
+```
+queuemail.username=******
+queuemail.password=******
+queuemail.idapp=******
+
+```
+
+Values of these properties are username and password of your QUEUEMAIL.DEV account and the app id are you going to use. You can create your app with [apps endpoint](api-apps.md).
+
+Now, we are going to use these DTO's:
+
+LogDTO.java:
+
+```
+package miapp.queuemail.dto;
+
+
+import java.time.LocalDateTime;
+
+public class LogDTO
+{
+    private String to;
+    private String resultcode;
+    private LocalDateTime when;
+
+    private String _id;
+
+    private String idsending;
+
+    private String idsmtp;
+
+    private String idapp;
+
+    private LocalDateTime created;
+
+    public String getTo() {
+        return to;
+    }
+
+    public void setTo(String to) {
+        this.to = to;
+    }
+
+    public String getResultcode() {
+        return resultcode;
+    }
+
+    public void setResultcode(String resultcode) {
+        this.resultcode = resultcode;
+    }
+
+    public LocalDateTime getWhen() {
+        return when;
+    }
+
+    public void setWhen(LocalDateTime when) {
+        this.when = when;
+    }
+
+    public String get_id() {
+        return _id;
+    }
+
+    public void set_id(String _id) {
+        this._id = _id;
+    }
+
+    public String getIdsending() {
+        return idsending;
+    }
+
+    public void setIdsending(String idsending) {
+        this.idsending = idsending;
+    }
+
+    public String getIdsmtp() {
+        return idsmtp;
+    }
+
+    public void setIdsmtp(String idsmtp) {
+        this.idsmtp = idsmtp;
+    }
+
+    public String getIdapp() {
+        return idapp;
+    }
+
+    public void setIdapp(String idapp) {
+        this.idapp = idapp;
+    }
+
+    public LocalDateTime getCreated() {
+        return created;
+    }
+
+    public void setCreated(LocalDateTime created) {
+        this.created = created;
+    }
+}
+
+```
+
+LoginResponseDTO.java:
+
+```
+package miapp.queuemail.dto;
+
+public class LoginResponseDTO
+{
+
+    private String token;
+    private String role;
+    private String userId;
+    private String username;
+    private String clientId;
+
+    public String getToken() {
+        return token;
+    }
+
+    public void setToken(String token) {
+        this.token = token;
+    }
+
+    public String getRole() {
+        return role;
+    }
+
+    public void setRole(String role) {
+        this.role = role;
+    }
+
+    public String getUserId() {
+        return userId;
+    }
+
+    public void setUserId(String userId) {
+        this.userId = userId;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getClientId() {
+        return clientId;
+    }
+
+    public void setClientId(String clientId) {
+        this.clientId = clientId;
+    }
+
+}
+
+```
+
+SendingResultDTO.java:
+```
+package miapp.queuemail.dto;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+@JsonInclude(JsonInclude.Include.NON_NULL)
+public class SendingResultDTO
+{
+    String id;
+    String status;
+    LocalDateTime inittime;
+    LocalDateTime logsdeleledby;
+    List<String> attachments;
+
+
+    List<String> blacklisted;
+    List<String> autoblacklisted;
+    List<String> notvalidrecipients;
+
+    List<LogDTO> log;
+    List<TrackingDTO> opened;
+    LocalDateTime finishtime;
+
+    String error;
+    Boolean localqueued;
+
+    public SendingResultDTO() {
+        super();
+    }
+
+    public SendingResultDTO(String id, String status, LocalDateTime inittime, LocalDateTime logsdeleledby, List<String> attachments, List<String> blacklisted, List<String> autoblacklisted, List<String> notvalidrecipients, List<LogDTO> log, List<TrackingDTO> opened, LocalDateTime finishtime, String error) {
+        this.id = id;
+        this.status = status;
+        this.inittime = inittime;
+        this.logsdeleledby = logsdeleledby;
+        this.attachments = attachments;
+        this.blacklisted = blacklisted;
+        this.autoblacklisted = autoblacklisted;
+        this.notvalidrecipients = notvalidrecipients;
+        this.log = log;
+        this.opened = opened;
+        this.finishtime = finishtime;
+        this.error = error;
+        this.localqueued = false;
+    }
+
+    public SendingResultDTO(String error)
+    {
+        this.error = error;
+        this.localqueued = false;
+    }
+
+    public SendingResultDTO(String error, Boolean localqueued)
+    {
+        this.error = error;
+        this.localqueued = localqueued;
+    }
+
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public List<String> getBlacklisted() {
+        return blacklisted;
+    }
+
+    public void setBlacklisted(List<String> blacklisted) {
+        this.blacklisted = blacklisted;
+    }
+
+    public List<String> getAutoblacklisted() {
+        return autoblacklisted;
+    }
+
+    public void setAutoblacklisted(List<String> autoblacklisted) {
+        this.autoblacklisted = autoblacklisted;
+    }
+
+    public List<String> getAttachments() {
+        return attachments;
+    }
+
+    public String getStatus() {
+        return status;
+    }
+
+    public void setStatus(String status) {
+        this.status = status;
+    }
+
+    public LocalDateTime getInittime() {
+        return inittime;
+    }
+
+    public void setInittime(LocalDateTime inittime) {
+        this.inittime = inittime;
+    }
+
+    public List<LogDTO> getLog() {
+        return log;
+    }
+
+    public void setLog(List<LogDTO> log) {
+        this.log = log;
+    }
+
+    public List<TrackingDTO> getOpened() {
+        return opened;
+    }
+
+    public void setOpened(List<TrackingDTO> opened) {
+        this.opened = opened;
+    }
+
+    public LocalDateTime getFinishtime() {
+        return finishtime;
+    }
+
+    public void setFinishtime(LocalDateTime finishtime) {
+        this.finishtime = finishtime;
+    }
+
+    public void setAttachments(List<String> attachments) {
+        this.attachments = attachments;
+    }
+
+    public List<String> getNotvalidrecipients() {
+        return notvalidrecipients;
+    }
+
+    public void setNotvalidrecipients(List<String> notvalidrecipients) {
+        this.notvalidrecipients = notvalidrecipients;
+    }
+
+    public String getError() {
+        return error;
+    }
+
+    public void setError(String error) {
+        this.error = error;
+    }
+
+    public LocalDateTime getLogsdeleledby() {
+        return logsdeleledby;
+    }
+
+    public void setLogsdeleledby(LocalDateTime logsdeleledby) {
+        this.logsdeleledby = logsdeleledby;
+    }
+
+    public Boolean getLocalqueued() {
+        return localqueued;
+    }
+
+    public void setLocalqueued(Boolean localqueued) {
+        this.localqueued = localqueued;
+    }
+
+}
+
+```
+
+TrackingDTO.java:
+```
+package miapp.queuemail.dto;
+
+
+import java.time.LocalDateTime;
+
+public class TrackingDTO
+{
+    private String email;
+    private LocalDateTime when;
+
+    private String _id;
+
+    private String idsending;
+
+    private String idmailing;
+
+    private String type; //OPEN, CLICK
+
+    private String url;
+
+    private LocalDateTime created;
+
+    private String ip;
+
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public LocalDateTime getWhen() {
+        return when;
+    }
+
+    public void setWhen(LocalDateTime when) {
+        this.when = when;
+    }
+
+    public String get_id() {
+        return _id;
+    }
+
+    public void set_id(String _id) {
+        this._id = _id;
+    }
+
+    public String getIdsending() {
+        return idsending;
+    }
+
+    public void setIdsending(String idsending) {
+        this.idsending = idsending;
+    }
+
+    public String getIdmailing() {
+        return idmailing;
+    }
+
+    public void setIdmailing(String idmailing) {
+        this.idmailing = idmailing;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public String getUrl() {
+        return url;
+    }
+
+    public void setUrl(String url) {
+        this.url = url;
+    }
+
+    public LocalDateTime getCreated() {
+        return created;
+    }
+
+    public void setCreated(LocalDateTime created) {
+        this.created = created;
+    }
+
+    public String getIp() {
+        return ip;
+    }
+
+    public void setIp(String ip) {
+        this.ip = ip;
+    }
+}
+
+```
+
+Now, we are going to define two entities to store failed emails in a local queue: 
+
+QueueEmail.java:
+```
+package miapp.queuemail.model;
+
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+@Document(collection = "queuemails")
+public class QueueEmail
+{
+    @Id
+    private String _id;
+
+    private String idapp;
+
+    private String idmailing;
+
+    private String from;
+
+    private String fromname;
+
+    private String to;
+
+    private String toname;
+
+    private String ccs;
+
+    private String bccs;
+
+    private String replyto;
+
+    private String subject;
+
+    private String subjectencoding;
+
+    private String body;
+
+    private String bodyencoding;
+
+    private String mimetype;
+
+    private String attachmentstype;
+
+    private List<String> urlattachments;
+
+    private Boolean includetracking;
+
+    private Boolean includeUnregisterLink;
+
+    private LocalDateTime senddate;
+
+    private Integer numretries;
+
+    private LocalDateTime created;
+
+    private LocalDateTime modified;
+
+
+    public QueueEmail()
+    {
+        this.numretries = 0;
+        this.created = this.modified = LocalDateTime.now();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        QueueEmail that = (QueueEmail) o;
+
+        return _id.equals(that._id);
+    }
+
+    @Override
+    public int hashCode() {
+        return _id.hashCode();
+    }
+
+    public String get_id() {
+        return _id;
+    }
+
+    public void set_id(String _id) {
+        this._id = _id;
+    }
+
+    public String getIdapp() {
+        return idapp;
+    }
+
+    public void setIdapp(String idapp) {
+        this.idapp = idapp;
+    }
+
+    public String getIdmailing() {
+        return idmailing;
+    }
+
+    public void setIdmailing(String idmailing) {
+        this.idmailing = idmailing;
+    }
+
+    public String getFrom() {
+        return from;
+    }
+
+    public void setFrom(String from) {
+        this.from = from;
+    }
+
+    public String getFromname() {
+        return fromname;
+    }
+
+    public void setFromname(String fromname) {
+        this.fromname = fromname;
+    }
+
+    public String getTo() {
+        return to;
+    }
+
+    public void setTo(String to) {
+        this.to = to;
+    }
+
+    public String getToname() {
+        return toname;
+    }
+
+    public void setToname(String toname) {
+        this.toname = toname;
+    }
+
+    public String getCcs() {
+        return ccs;
+    }
+
+    public void setCcs(String ccs) {
+        this.ccs = ccs;
+    }
+
+    public String getBccs() {
+        return bccs;
+    }
+
+    public void setBccs(String bccs) {
+        this.bccs = bccs;
+    }
+
+    public String getReplyto() {
+        return replyto;
+    }
+
+    public void setReplyto(String replyto) {
+        this.replyto = replyto;
+    }
+
+    public String getSubject() {
+        return subject;
+    }
+
+    public void setSubject(String subject) {
+        this.subject = subject;
+    }
+
+    public String getSubjectencoding() {
+        return subjectencoding;
+    }
+
+    public void setSubjectencoding(String subjectencoding) {
+        this.subjectencoding = subjectencoding;
+    }
+
+    public String getBody() {
+        return body;
+    }
+
+    public void setBody(String body) {
+        this.body = body;
+    }
+
+    public String getBodyencoding() {
+        return bodyencoding;
+    }
+
+    public void setBodyencoding(String bodyencoding) {
+        this.bodyencoding = bodyencoding;
+    }
+
+    public String getMimetype() {
+        return mimetype;
+    }
+
+    public void setMimetype(String mimetype) {
+        this.mimetype = mimetype;
+    }
+
+    public String getAttachmentstype() {
+        return attachmentstype;
+    }
+
+    public void setAttachmentstype(String attachmentstype) {
+        this.attachmentstype = attachmentstype;
+    }
+
+    public Boolean getIncludetracking() {
+        return includetracking;
+    }
+
+    public void setIncludetracking(Boolean includetracking) {
+        this.includetracking = includetracking;
+    }
+
+    public Boolean getIncludeUnregisterLink() {
+        return includeUnregisterLink;
+    }
+
+    public void setIncludeUnregisterLink(Boolean includeUnregisterLink) {
+        this.includeUnregisterLink = includeUnregisterLink;
+    }
+
+    public LocalDateTime getSenddate() {
+        return senddate;
+    }
+
+    public void setSenddate(LocalDateTime senddate) {
+        this.senddate = senddate;
+    }
+
+    public Integer getNumretries() {
+        return numretries;
+    }
+
+    public void setNumretries(Integer numretries) {
+        this.numretries = numretries;
+    }
+
+    public LocalDateTime getCreated() {
+        return created;
+    }
+
+    public void setCreated(LocalDateTime created) {
+        this.created = created;
+    }
+
+    public LocalDateTime getModified() {
+        return modified;
+    }
+
+    public void setModified(LocalDateTime modified) {
+        this.modified = modified;
+    }
+
+    public List<String> getUrlattachments() {
+        return urlattachments;
+    }
+
+    public void setUrlattachments(List<String> urlattachments) {
+        this.urlattachments = urlattachments;
+    }
+}
+```
+
+QueueEmailAttachment.java:
+```
+package miapp.queuemail.model;
+
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+@Document(collection = "queuemails_attachments")
+public class QueueEmailAttachment
+{
+    @Id
+    private String _id;
+
+    private String idemail;
+
+    private String filepath;
+
+    private Boolean removeAfterSent;
+
+
+    public QueueEmailAttachment()
+    {
+        this.removeAfterSent = false;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        QueueEmailAttachment that = (QueueEmailAttachment) o;
+
+        return _id.equals(that._id);
+    }
+
+    @Override
+    public int hashCode() {
+        return _id.hashCode();
+    }
+
+
+    public String get_id() {
+        return _id;
+    }
+
+    public void set_id(String _id) {
+        this._id = _id;
+    }
+
+    public String getIdemail() {
+        return idemail;
+    }
+
+    public void setIdemail(String idemail) {
+        this.idemail = idemail;
+    }
+
+    public String getFilepath() {
+        return filepath;
+    }
+
+    public void setFilepath(String filepath) {
+        this.filepath = filepath;
+    }
+
+    public Boolean getRemoveAfterSent() {
+        return removeAfterSent;
+    }
+
+    public void setRemoveAfterSent(Boolean removeAfterSent) {
+        this.removeAfterSent = removeAfterSent;
+    }
+}
+```
+
+Now, we are going to define repositories for these entities:
+
+QueueEmailsRepository.java:
+```
+package miapp.queuemail.repositories;
+
+import miapp.queuemail.model.QueueEmail;
+import org.springframework.data.mongodb.repository.MongoRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+
+@Repository
+public interface QueueEmailsRepository extends MongoRepository<QueueEmail, String>
+{
+
+	List<QueueEmail> findAll();
+}
+```
+
+QueueEmailAttachmentsRepository.java:
+```
+package miapp.queuemail.repositories;
+
+import miapp.queuemail.model.QueueEmailAttachment;
+import org.springframework.data.mongodb.repository.MongoRepository;
+import org.springframework.data.mongodb.repository.Query;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+@Repository
+public interface QueueEmailAttachmentsRepository extends MongoRepository<QueueEmailAttachment, String>
+{
+
+	@Query("{ 'idemail' : ?0 }")
+	List<QueueEmailAttachment> findByEmail(String idemail);
+
+	@Query(value="{'idemail' : ?0}", delete = true)
+	public void deleteByEmail(String idemail);
+}
+
+```
+
+Now, we will define the service with only two API operations (login and send emails) and a scheduled method in order to process our local queue:
+
+QueuemailHardyService.java:
+
+```
+package miapp.queuemail.dev.service;
+
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import miapp.queuemail.repositories.QueueEmailAttachmentsRepository;
+import miapp.queuemail.repositories.QueueEmailsRepository;
+import miapp.queuemail.model.QueueEmail;
+import miapp.queuemail.model.QueueEmailAttachment;
+import miapp.queuemail.dto.LoginResponseDTO;
+import miapp.queuemail.dto.SendingResultDTO;
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.fluent.Form;
+import org.apache.http.client.fluent.Request;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.entity.ContentType;
+import org.apache.http.entity.mime.MultipartEntityBuilder;
+import org.apache.http.entity.mime.content.FileBody;
+import org.apache.http.entity.mime.content.StringBody;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Service;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.InputStreamReader;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.List;
+
+
+
+@Service
+public class QueuemailHardyService
+{
+    private static final String API_MAIN_URL = "https://api.queuemail.dev/api";
+
+    @Value("${queuemail.username}")
+    private String username;
+
+    @Value("${queuemail.password}")
+    private String password;
+
+    @Value("${queuemail.idapp}")
+    private String idapp;
+
+    final QueueEmailsRepository queueEmailsRepository;
+    final QueueEmailAttachmentsRepository queueEmailAttachmentsRepository;
+
+    public QueuemailHardyService(QueueEmailsRepository queueEmailsRepository, QueueEmailAttachmentsRepository queueEmailAttachmentsRepository)
+    {
+        this.queueEmailsRepository = queueEmailsRepository;
+        this.queueEmailAttachmentsRepository = queueEmailAttachmentsRepository;
+    }
+
+
+    public LoginResponseDTO login() throws Exception
+    {
+        try
+        {
+            HttpResponse response = Request.Post(API_MAIN_URL + "/auth/login").bodyForm(Form.form()
+                    .add("username", username)
+                    .add("password", password)
+                    .build()).execute().returnResponse();
+
+            if (response.getStatusLine().getStatusCode() == 200)
+            {
+                ObjectMapper mapper = new ObjectMapper();
+                mapper.enable(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);
+                mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+                LoginResponseDTO res =  mapper.readValue(response.getEntity().getContent(), LoginResponseDTO.class);
+                return res;
+            }
+            else if (response.getStatusLine().getStatusCode() == 403)
+            {
+                throw new Exception("USER_PASSWORD_NOT_VALID");
+            }
+            else
+            {
+                throw new Exception("ERROR_LOGIN");
+            }
+        }
+        catch(Exception e)
+        {
+            e.printStackTrace();
+            throw new Exception("GENERAL_ERROR");
+        }
+    }
+
+    public SendingResultDTO sendEmail(String token,
+                                      String from, String fromname, String to, String toname,
+                                      String ccs, String bccs, String replyto,
+                                      String subject, String subjectencoding, String body, String bodyencoding,
+                                      String mimetype,
+                                      List<File> attachments,
+                                      List<String> urlattachments,
+                                      String attachmenttype,
+                                      Boolean includetracking,
+                                      Boolean includeunregisterlink,
+                                      Boolean localqueue,
+                                      Boolean removeAttachmentsAfterSent)
+    {
+        try
+        {
+            final SendingResultDTO[] res = new SendingResultDTO[1];
+
+            if(token==null) token = this.login().getToken();
+            if(token==null)
+            {
+                return new SendingResultDTO("AUTH_ERROR",
+                        this.queueEmail(idapp,
+                                from, fromname, to, toname,
+                                ccs, bccs, replyto,
+                                subject, subjectencoding, body, bodyencoding,
+                                mimetype,
+                                attachments,
+                                urlattachments,
+                                attachmenttype,
+                                includetracking,
+                                includeunregisterlink,
+                                localqueue,
+                                removeAttachmentsAfterSent));
+            }
+
+            HttpPost httppost = new HttpPost(API_MAIN_URL + "/private/emails/send");
+            httppost.addHeader("Authorization", "Bearer " + token);
+
+            MultipartEntityBuilder mpeb = MultipartEntityBuilder.create();
+
+            if(attachments!=null && attachments.size()>0)
+                for(File mf : attachments)
+                {
+                    mpeb.addPart("attachments", new FileBody(mf));
+                }
+
+            mpeb.addPart("idapp", new StringBody(idapp, ContentType.TEXT_PLAIN));
+            if(from!=null) mpeb.addPart("from", new StringBody(from, ContentType.TEXT_PLAIN));
+            if(fromname!=null) mpeb.addPart("fromname", new StringBody(fromname, ContentType.TEXT_PLAIN));
+            if(to!=null) mpeb.addPart("tos", new StringBody(to, ContentType.TEXT_PLAIN));
+            if(toname!=null) mpeb.addPart("tonames", new StringBody(toname, ContentType.TEXT_PLAIN));
+            if(ccs!=null) mpeb.addPart("ccs", new StringBody(ccs, ContentType.TEXT_PLAIN));
+            if(bccs!=null) mpeb.addPart("bccs", new StringBody(bccs, ContentType.TEXT_PLAIN));
+            if(replyto!=null) mpeb.addPart("replyto", new StringBody(replyto, ContentType.TEXT_PLAIN));
+            if(subject!=null) mpeb.addPart("subject", new StringBody(subject, ContentType.TEXT_PLAIN));
+            if(subjectencoding!=null) mpeb.addPart("subjectencoding", new StringBody(subjectencoding, ContentType.TEXT_PLAIN));
+            if(body!=null) mpeb.addPart("body", new StringBody(body, ContentType.TEXT_PLAIN));
+            if(bodyencoding!=null) mpeb.addPart("bodyencoding", new StringBody(bodyencoding, ContentType.TEXT_PLAIN));
+            if(mimetype!=null) mpeb.addPart("mimetype", new StringBody(mimetype, ContentType.TEXT_PLAIN));
+            if(attachmenttype!=null) mpeb.addPart("attachmenttype", new StringBody(attachmenttype, ContentType.TEXT_PLAIN));
+            if(urlattachments!=null) mpeb.addPart("urlattachments", new StringBody(String.join(",", urlattachments), ContentType.TEXT_PLAIN));
+            if(includetracking!=null) mpeb.addPart("includetracking", new StringBody(""+includetracking, ContentType.TEXT_PLAIN));
+            if(includeunregisterlink!=null) mpeb.addPart("includeunregisterlink", new StringBody(""+includeunregisterlink, ContentType.TEXT_PLAIN));
+
+            HttpEntity reqEntity = mpeb.build();
+            httppost.setEntity(reqEntity);
+
+            ObjectMapper mapper = new ObjectMapper();
+            mapper.enable(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);
+            mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+            mapper.registerModule(new JavaTimeModule());
+
+            try(CloseableHttpClient client = HttpClientBuilder.create().build())
+            {
+                client.execute(httppost, response -> {
+                    if (response.getStatusLine().getStatusCode() == 200)
+                    {
+                        if(removeAttachmentsAfterSent!=null && removeAttachmentsAfterSent==true)
+                            for(File file : attachments) try { file.delete(); } catch (Exception e) { e.printStackTrace();}
+
+                        res[0] = mapper.readValue(response.getEntity().getContent(), SendingResultDTO.class);
+                    }
+                    else if (response.getStatusLine().getStatusCode() == 401)
+                    {
+                        res[0] = new SendingResultDTO("Not authorized", false);
+                    }
+                    else if (response.getStatusLine().getStatusCode() == 403)
+                    {
+                        res[0] = new SendingResultDTO("Credentials not valid", false);
+                    }
+                    else if (response.getStatusLine().getStatusCode() == 406)
+                    {
+                        String responseString = "";
+                        BufferedReader br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
+                        String readLine;
+                        while (((readLine = br.readLine()) != null)) responseString += readLine;
+                        br.close();
+                        res[0] = new SendingResultDTO(responseString,
+                        this.queueEmail(idapp,
+                                from, fromname, to, toname,
+                                ccs, bccs, replyto,
+                                subject, subjectencoding, body, bodyencoding,
+                                mimetype,
+                                attachments,
+                                urlattachments,
+                                attachmenttype,
+                                includetracking,
+                                includeunregisterlink,
+                                localqueue==null?false:localqueue,
+                                removeAttachmentsAfterSent==null?false:removeAttachmentsAfterSent));
+                    }
+                    else
+                    {
+                        res[0] = new SendingResultDTO("ERROR_SENDING_EMAIL",
+                        this.queueEmail(idapp,
+                                from, fromname, to, toname,
+                                ccs, bccs, replyto,
+                                subject, subjectencoding, body, bodyencoding,
+                                mimetype,
+                                attachments,
+                                urlattachments,
+                                attachmenttype,
+                                includetracking,
+                                includeunregisterlink,
+                                localqueue==null?false:localqueue,
+                                removeAttachmentsAfterSent==null?false:removeAttachmentsAfterSent));
+                    }
+
+                    return res[0];
+                });
+
+
+            } catch (Exception e) { throw e; }
+
+            return res[0];
+        }
+        catch(Exception e)
+        {
+            e.printStackTrace();
+            return new SendingResultDTO("GENERAL_ERROR",
+                    this.queueEmail(idapp,
+                            from, fromname, to, toname,
+                            ccs, bccs, replyto,
+                            subject, subjectencoding, body, bodyencoding,
+                            mimetype,
+                            attachments,
+                            urlattachments,
+                            attachmenttype,
+                            includetracking,
+                            includeunregisterlink,
+                            localqueue==null?false:localqueue,
+                            removeAttachmentsAfterSent==null?false:removeAttachmentsAfterSent));
+        }
+    }
+
+
+    private boolean queueEmail(String idapp,
+                            String from, String fromname, String to, String toname,
+                            String ccs, String bccs, String replyto,
+                            String subject, String subjectencoding, String body, String bodyencoding,
+                            String mimetype,
+                            List<File> attachments,
+                            List<String> urlattachments,
+                            String attachmenttype,
+                            Boolean includetracking,
+                            Boolean includeunregisterlink,
+                            Boolean localqueue,
+                            Boolean removeAttachmentsAfterSent)
+    {
+        try
+        {
+            if(!localqueue) return  false;
+
+            QueueEmail queueEmail = new QueueEmail();
+            queueEmail.setIdapp(idapp);
+            queueEmail.setFrom(from);
+            queueEmail.setFromname(fromname);
+            queueEmail.setTo(to);
+            queueEmail.setToname(toname);
+            queueEmail.setCcs(ccs);
+            queueEmail.setBccs(bccs);
+            queueEmail.setReplyto(replyto);
+            queueEmail.setSubject(subject);
+            queueEmail.setSubjectencoding(subjectencoding);
+            queueEmail.setBody(body);
+            queueEmail.setBodyencoding(bodyencoding);
+            queueEmail.setMimetype(mimetype);
+            queueEmail.setUrlattachments(urlattachments);
+            queueEmail.setAttachmentstype(attachmenttype);
+            queueEmail.setIncludetracking(includetracking);
+            queueEmail.setIncludeUnregisterLink(includeunregisterlink);
+            queueEmail = this.queueEmailsRepository.save(queueEmail);
+
+            if (attachments != null && attachments.size() > 0)
+                for (File file : attachments) {
+                    QueueEmailAttachment queueEmailAttachment = new QueueEmailAttachment();
+                    queueEmailAttachment.setIdemail(queueEmail.get_id());
+                    queueEmailAttachment.setFilepath(file.getAbsolutePath());
+                    queueEmailAttachment.setRemoveAfterSent(removeAttachmentsAfterSent);
+                    this.queueEmailAttachmentsRepository.save(queueEmailAttachment);
+                }
+
+            return true;
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace();
+            return false;
+        }
+    }
+
+    @Scheduled(fixedRate = 1000*60*5) // 5 minutes
+    public void processQueuedEmails()
+    {
+        try
+        {
+            List<QueueEmail> pendingemails = this.queueEmailsRepository.findAll(); //TODO: improve sorting in order to better selection based on created or numretries
+            if(pendingemails==null || pendingemails.size()==0) return;
+
+            System.out.println("\n" + LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS")) + " - Procesing queued email.");
+
+            String token = this.login().getToken();
+            if(token==null) throw new Exception("NO VALID TOKEN");
+
+            for(QueueEmail queueEmail : pendingemails)
+            {
+                try
+                {
+                    List<File> attachments = null;
+                    List<QueueEmailAttachment> qattachments = this.queueEmailAttachmentsRepository.findByEmail(queueEmail.get_id());
+                    if(qattachments!=null && qattachments.size()>0)
+                    {
+                        attachments = new ArrayList<>(qattachments.size());
+                        for(QueueEmailAttachment queueEmailAttachment : qattachments)
+                            attachments.add(new File(queueEmailAttachment.getFilepath()));
+                    }
+
+                    SendingResultDTO sendingResultDTO = this.sendEmail(token,
+                            queueEmail.getFrom(), queueEmail.getFromname(),  queueEmail.getTo(), queueEmail.getToname(),
+                            queueEmail.getCcs(), queueEmail.getBccs(), queueEmail.getReplyto(),
+                            queueEmail.getSubject(), queueEmail.getSubjectencoding(), queueEmail.getBody(), queueEmail.getBodyencoding(),
+                            queueEmail.getMimetype(),
+                            attachments,
+                            queueEmail.getUrlattachments(),
+                            queueEmail.getAttachmentstype(),
+                            queueEmail.getIncludetracking(),
+                            queueEmail.getIncludeUnregisterLink(),
+                            false, //at queue process do not queue up again!
+                            null);
+
+                    if(sendingResultDTO==null || sendingResultDTO.getStatus()==null || sendingResultDTO.getError()!=null)
+                    {
+                        queueEmail.setNumretries(queueEmail.getNumretries()+1);
+                        queueEmail.setModified(LocalDateTime.now());
+                        this.queueEmailsRepository.save(queueEmail);
+                    }
+                    else
+                    {
+                        this.queueEmailsRepository.delete(queueEmail);
+                        try
+                        {
+                            if(qattachments!=null && qattachments.size()>0)
+                            {
+                                for(QueueEmailAttachment queueEmailAttachment : qattachments)
+                                   if(queueEmailAttachment.getRemoveAfterSent())
+                                       new File(queueEmailAttachment.getFilepath()).delete();
+                            }
+                        }
+                        catch (Exception e) { e.printStackTrace(); }
+                        this.queueEmailAttachmentsRepository.deleteByEmail(queueEmail.get_id());
+                    }
+                }
+                catch (Exception e)
+                {
+                    try { queueEmail.setNumretries(queueEmail.getNumretries()+1); queueEmail.setModified(LocalDateTime.now()); this.queueEmailsRepository.save(queueEmail); } catch (Exception ee) {}
+                    e.printStackTrace();
+                }
+            }
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace();
+        }
+    }
+
+}
+
+```
+
+At this point we have all the necessary code to replace our usual way to send emails:
+
+```
+SendEmail.send( fromemail, toemail, subject, body );
+````
+
+with our new and more robust way:
+
+```
+        @Autowired
+        QueuemailHardyService queuemailHardyService;
+
+        [...]
+
+		SendingResultDTO sendingResultDTO = this.queuemailHardyService.sendEmail(null, fromemail, "Mi name",  toemail, "Your name", null, null, fromemail,
+				subject, "UTF-8", body, "UTF-8", "text/html",
+				null, null, null,
+				true, false,
+				true, null);
+
+		if(sendingResultDTO==null || (sendingResultDTO.getLocalqueued()!=null && sendingResultDTO.getLocalqueued()==false) )
+		{
+			SendEmail.send( fromemail, toemail, subject, body ); // we will send using usual way as failover
+		}
+```
+You can made more control on email status, code errors, etc. Also yo can control how many times emails are retried in the local queue using the *SendingResultDTO.numretries* field.
+
+
diff --git a/other-faqs.md b/other-faqs.md
index bee3de2..96f7aea 100644
--- a/other-faqs.md
+++ b/other-faqs.md
@@ -1,3 +1,9 @@
+### What happens if there are network outages or server downtime while calling QUEUEMAIL.DEV API?
+
+The solution is to implement a local queue to store failed emails when QUEUEMAIL.DEV does not respond.
+
+[Hardy client example](examples-hardyservice.md) shows you how to implement this local queue.
+
 
 ### Can I send emails using my custom domain email address?