At-least-once delivery is the default for most queues and streams, so consumers must be idempotent. My go-to pattern is a processed_events table keyed by event_id with a unique constraint. When a message arrives, the consumer tries to insert event_id;

Sometimes you want a quick diagnostic without wiring a full metrics stack. expvar exposes variables at /debug/vars in a standard JSON format. I use it for a handful of counters like “requeststotal” and “jobsfailed” when I’m bootstrapping a service or

In containerized environments, the Go runtime can benefit from knowing the memory budget. With Go 1.19+, debug.SetMemoryLimit lets you set a soft limit so the GC reacts more aggressively before the process gets killed by the OOM killer. I treat this a

For high-throughput endpoints that serialize JSON or build strings repeatedly, allocations can become a real cost. sync.Pool is a pragmatic tool for reusing temporary buffers without manual free lists. The key is to treat pooled objects as ephemeral:

Pub/Sub consumers should assume connections will drop: Redis restarts, network blips, or idle timeouts happen. I keep the subscription loop simple: subscribe, range over the channel, and exit cleanly when ctx.Done() fires. If the subscription ends une

When using sqlc, the generated query set usually has a WithTx method. I wrap that pattern so business logic can depend on an interface and still run inside a transaction. The key is to keep transaction boundaries explicit while avoiding passing *sql.T

Not every integration payload maps cleanly to a static struct. When I need to accept “mostly known” JSON but preserve unknown fields for auditing or forward compatibility, I use json.RawMessage. That allows me to decode the envelope (event name, versi

A lot of handler complexity disappears if you reject bad requests early. I enforce the HTTP method (POST, PUT, etc.) and require Content-Type: application/json before attempting to decode. This prevents confusing errors where clients send form-encoded

For internal admin endpoints, I often add a network allowlist in addition to auth. The tricky part is deciding which IP to trust: if you’re behind a proxy, you might need X-Forwarded-For, but only if the proxy is controlled by you. The middleware belo

If you expose an API to the public internet, you need a basic guardrail against bursts. I like a token bucket with rate.NewLimiter because it’s easy to reason about: steady-state rate plus a burst capacity. The middleware checks Allow() and returns 42

I often need a fast read path for small datasets (like a list of active plans or an allowlist) that updates periodically. Instead of locking on every read, I store a pointer to an immutable snapshot in atomic.Pointer. Reads are lock-free and safe; ref

Structured logs are great, but at high QPS they can become their own outage: too much IO, too much storage, and noisy dashboards. zap includes a sampler that allows you to keep early logs and then sample at a fixed rate. I like this for “successful re