How would you make a payment processor web/app technology wise?

Question

You are about to start a payment processor startup like Stripe and Paypal, what technology would you for what part use and why?

Cyph0n · Accepted Answer

I&rsquo;m actually working on a toy payment processor for fun and to learn some new tech.The tech I&rsquo;ve chosen:- Postgres for the DB- Redis for caching + queues- Go for the customer-facing backend services- Rust for the bank-facing services- gRPC for internal communication- TypeScript + React for the frontend checkout app- HashiCorp stack for deployment

weitzj · Answer

Postgres for the database for the start and maybe this does suffice. Maybe think now how you could model a transaction with something like Cassandra. Only append the data. No updates to transactions. The balance is the sum over all transactions over time. Use something like a double entry bookkeeping system so you don’t make up any money out of thin air.
Keep in mind how to do reconciliation, what is a transaction, how to do idempotency.
For the backend Erlang/BEAM.