If you want to know how payment systems are implemented, just look at the API documentation of one of the payment gateways ⚡
The available APIs and their signatures reveal a lot of details and a few terms that should catch your eye are
- idempotency key
- webhooks and rate limit
- handling failures and retries
- static IP addresses and certs
- transient and semi-transient failures
- backoff schedule to address thundering herd
Fun fact, most payments SDKs handle DNS caching on our behalf ⚡
By the way, here’s how Razorpay has built and scaled its notification service
watch - youtu.be/DQwlmTvs6xA
⚡ I keep writing and sharing these engineering nuggets, so if you are keen on learning them, follow along.
no fluff; just engineering.