Go Payment Processor

Simulates a secure implementation of internal wallets transfers and external payments operations in a Fintech system. It demonstrates the use atomic database transactions and idempotency keys to prevent race conditions, double processing, and handling concurrent requests properly. It also shows the use of ledger entries to keep accurate accounting records in a Fintech system.

• Wallet Funding: Simulates funding wallet from an external source e.g virtual account credit
• Internal Wallet Transfer: Simulates transfer between wallets, accounts for race conditions and idempotency.
• External Bank Transfer: Simulates USD/GRP/EUR transfers to external bank accounts.

Setup with Docker

1) Clone repo

git clone https://github.com/jesseinvent/go-payment-processor

2) Build with Docker and run migrations

make build-docker

Endpoints

Create user - Simulates user registration

curl -X POST http://localhost:5001/api/v1/users \
-H "Content-Type: application/json" \
-d '{
  "name": "James",
  "email": "james@example.com",
  "phoneNumber": "09037148367"
}'

Get user - Simulates fetching user details e.g during login

curl -X GET http://localhost:5001/api/v1/users/1

Create Currency - Simulates adding a new currency to the system

curl -X POST http://localhost:5001/api/v1/currencies \
-H "Content-Type: application/json" \
-d '{
  "name": "USD",
  "symbol": "USD",
  "baseUnitFactor": 100,
  "iconUrl": "https://usd-icon.png"
}'

Get Currencies - Simulates fetching all available currencies in the system

curl -X GET http://localhost:5001/api/v1/currencies

Create wallet for user - Simulates wallet creation for a user in a specific currency

curl -X POST http://localhost:5001/api/v1/wallets \
-H "Content-Type: application/json" \
-d '{
  "userId": 1,
  "currencyId": 1
}'

Get user wallet details - Simulates fetching a user's wallets details including balance and currency information

curl -X GET http://localhost:5001/api/v1/wallets/user/1

Fund wallet - Simulates funding a user's wallet from an external source

curl -X POST http://localhost:5001/api/v1/payments/fund-wallet \
-H "Content-Type: application/json" \
-d '{
  "userId": 1,
  "walletId": 1,
  "amount": 1000
}'

Internal wallet transfer - Simulates transferring payments in a specific currency between two wallets within the system

curl -X POST http://localhost:5001/api/v1/payments/internal-transfer \
-H "Content-Type: application/json" \
-H "Idempotency-Key: <unique-uuid-key>" \
-d '{
  "senderUserId": 2,
  "receiverUserId": 1,
  "currencyId": 1,
  "amount": 20.5
}'

External bank transfer - Simulates transferring payments in a specific currency from a user's wallet to an external bank account

curl -X POST http://localhost:5001/api/v1/payments/external-bank-transfer \
-H "Content-Type: application/json" \
-H "Idempotency-Key: <unique-uuid-key>" \
-d '{
  "senderUserId": 1,
  "currencyId": 1,
  "amount": 10.5,
  "beneficiaryName": "John Doe",
  "beneficiaryAccountNumber": "1234568951",
  "beneficiaryBankCode": "133",
  "swiftCode": "11111",
  "sortCode": "0000"
}'

Get transaction history - Simulates fetching a user's transaction history

curl -X GET "http://localhost:5001/api/v1/transactions/user/1"