reliability

A simple fixed-window rate limiter is often enough for endpoints like login, password reset, webhooks, or expensive searches. Use atomic Redis INCR + EXPIRE with a stable key and return remaining quota for UX.

In production, stack traces without context are slow to debug. Raise custom exceptions that include IDs and safe metadata, and log them as JSON. This is the difference between “we think” and “we know”.

Cleanup paths are easy to under-test, and it’s common to ignore close errors because you only have one return value. With Go 1.20+, errors.Join gives you a clean way to accumulate multiple cleanup errors and return them as a single error value. This i

If you fan out work (HTTP calls, DB reads, image processing), the failure mode isn’t just “slow,” it’s “everything gets slow” because you saturate CPU or downstream connections. A semaphore is a simple way to cap concurrency. The important part is mak

I generally prefer running migrations in a separate release step, but for smaller deployments it’s sometimes pragmatic to run them at startup. The failure mode to avoid is “every instance runs migrations at once.” The pattern here uses Postgres adviso

When a dependency is failing, you don’t want to keep hammering it. A simple circuit breaker trips after N failures and short-circuits for a cooldown window. It protects your app and your vendor.