diff --git a/lib/sources/AppleMusic.ts b/lib/sources/AppleMusic.ts
index 1090e90..dbeb65e 100644
--- a/lib/sources/AppleMusic.ts
+++ b/lib/sources/AppleMusic.ts
@@ -182,9 +182,9 @@ export default class AppleMusic extends AbstractExternalSource {
     });
 
     if (res.statusCode === 200) {
-      return res.body.json();
+      return res.body.json() as T;
     } else {
-      return new AppleMusicError(await res.body.json());
+      return new AppleMusicError(await res.body.json() as IErrorResponse);
     }
   }
 
diff --git a/lib/sources/Deezer.ts b/lib/sources/Deezer.ts
index 667dcec..4bc3ce5 100644
--- a/lib/sources/Deezer.ts
+++ b/lib/sources/Deezer.ts
@@ -92,13 +92,13 @@ export default class Deezer extends AbstractExternalSource {
   }
 
   private async makeRequest<T>(endpoint: string): Promise<T | DeezerError> {
-    const res = await request(`https://api.deezer.com/${endpoint}`).then(r => r.body.json());
+    const res = await request(`https://api.deezer.com/${endpoint}`).then(r => r.body.json()) as IDeezerResponse;
 
     if (res.error) {
       return new DeezerError(res.error.type, res.error.message);
     }
 
-    return res;
+    return res as T;
   }
 }
 
@@ -116,6 +116,10 @@ class DeezerError implements IDeezerError {
   }
 }
 
+interface IDeezerResponse {
+  error?: IDeezerError;
+}
+
 interface IDeezerError {
   type: string;
   message: string;
diff --git a/lib/sources/Spotify.ts b/lib/sources/Spotify.ts
index dc1354a..a443ebe 100644
--- a/lib/sources/Spotify.ts
+++ b/lib/sources/Spotify.ts
@@ -206,13 +206,13 @@ export default class Spotify extends AbstractExternalSource {
       headers: {
         Authorization: this.token as string,
       }
-    }).then(r => r.body.json());
+    }).then(r => r.body.json()) as ISpotifyResponse;
 
     if (res.error) {
       return new SpotifyError(res.error.message);
     }
 
-    return res;
+    return res as T;
   }
 
   private async renewToken() {
@@ -266,6 +266,10 @@ class SpotifyError implements ISpotifyError {
   }
 }
 
+interface ISpotifyResponse {
+  error?: ISpotifyError;
+}
+
 interface ISpotifyError {
   message: string;
 }