money-transfers-api

Revolut backend test assignment. Simple API for money transfers between accounts, implemented in Go.

Building and running

First, install dependencies:

go get ./...

Here I'm using only two dependencies:

• toml - for parsing the config file;
• sqlite3 - as the embedded database;

Then you can build and test the project:

make && make test

To build the static binary for linux (~12Mb):

make build-static

After a successful build, you only have to run binary to start the server:

./apiserver --config-path="configs/apiserver.toml"

API Reference

Server uses int64 numbers to represent the money, to make all calculations without computation errors.
To get the real value - just convert integer to float and divide the value by 100, and do everything in reverse order to convert real value to integer.

• GET /health:
  • curl -v -X GET http://localhost:8010/health;
  • Returns OK if server is up and running;
• POST /api/v1/accounts:
  • Gets integer balance value:

    curl -v -X POST \
         -H "Content-Type: application/json" \
         --data '{"balance": 10000}' \
         http://localhost:8010/api/v1/accounts
    

  • Returns account structure filled with created id:

    {
       "account_id":1,
    }  
    

• DELETE /api/v1/accounts:
  • Gets account_id:

    curl -v -X DELETE -G \
         -d account_id=1 \
          http://localhost:8010/api/v1/accounts
    

  • Returns no payload - just 204 code if the deletion was successful;
• GET /api/v1/accounts:
  • Gets account_id:

    curl -v -X GET -G \
         -d account_id=1 \
         http://localhost:8010/api/v1/accounts
    

  • Returns account with the current balance value:

    {
       "account_id":1,
       "balance":10000
    }  
    

• POST /api/v1/transfer-money:
  • Gets two account_id values and amount of money to transfer:

    curl -v -X POST \
         -H "Content-Type: application/json" \
         --data '{"from_account_id": 1, "to_account_id": 2, "amount": 5000}' \
         http://localhost:8010/api/v1/transfer-money
    

  • Returns 204 status code if the money transfer was successful;
• GET /api/v1/transactions:
  • Gets account_id, n_days period to query transactions log and limit on resulting list length:

    curl -v -X GET -G \
         -d account_id=2 \
         -d n_last_days=1 \
         -d limit=3 \
         http://localhost:8010/api/v1/transactions
    

  • Returns list of transactions for the requested account:

    [
      {
        "timestamp":"2021-05-16T08:56:36.953Z",
        "from_account_id":1,
        "to_account_id":2,
        "amount":5000
      },
      {
        "timestamp":"2021-05-16T09:09:32.396Z",
        "from_account_id":1,
        "to_account_id":2,
        "amount":1000
      },
      {
        "timestamp":"2021-05-16T09:09:34.423Z",
        "from_account_id":1,
        "to_account_id":2,
        "amount":1000
      }
    ]