curl --request POST \
  --url https://api.mpesaflow.dev/express \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "phoneNumber": "254712345678",
  "amount": "100.00",
  "transactionDesc": "mpesaflow",
  "type": "payment",
  "customerName": "John Doe",
  "accountReference": "mpesaflow",
  "metadata": {}
}'

{
  "status": "completed",
  "message": "Transaction completed successfully",
  "amount": "100.00",
  "phoneNumber": "254712345678",
  "transactionId": "trxn_YGZBY32PBBavYbhL",
  "type": "payment",
  "timestamp": "2025-07-13T18:10:00Z"
}