The moment you split ‘write to DB’ and ‘publish to a queue’ into two independent operations, you create a place to lose data. Publish first and a DB failure means consumers act on something that never happened. Write first and a publish failure means

I reached for idempotency the moment retries started duplicating side effects. In Advisory lock helper, I generate a deterministic lock ID and use pg_try_advisory_lock to ensure only one worker owns the critical section; the ensure block always calls

Custom managers encapsulate common query patterns. I create a manager method for each frequently-used filter like published() or active(). By returning self, I can chain manager methods. For more complex queries, I create a custom QuerySet class and u

Rails’ built-in encryption makes it easier to protect PII at rest. Use it for fields like phone numbers or external tokens. Combine with deterministic encryption when you need lookup-by-value.

Once services talk to other services, logs alone don’t tell you where time goes. I like OpenTelemetry because it’s vendor-neutral: export to Honeycomb, Datadog, Tempo—whatever your team uses. I keep the initial setup minimal: instrument http, express,

For queries too complex for the ORM, I use raw SQL. The raw() method returns model instances. I use cursor.execute() for non-model queries. I always use parameterized queries to prevent SQL injection—never string interpolation. For reporting, raw SQL

Window functions perform calculations across rows related to the current row. I use them for running totals, rankings, and moving averages. Django's Window expression with functions like RowNumber, Rank, DenseRank provide SQL window function support.

Authorization filters often become string-SQL soup. Use Arel to build composable scopes that are still readable and safe. This snippet shows a “visible_to(member)” scope with a join and a condition that can evolve without turning into interpolated SQL

Sometimes exact counters aren’t worth the write cost. For high-traffic views, track increments in Redis and periodically aggregate into the DB. It’s an operational tradeoff that can dramatically reduce DB pressure.

Extending Django's user model should be done early in projects. I use AbstractBaseUser for full control or AbstractUser to extend the default. Setting AUTH_USER_MODEL points Django to my custom model. I add fields like phone, avatar, or preferences. F

Full reindexes can be long and fragile. Add checkpoints (last processed id), process in batches, and make it resumable. That turns a scary operation into a routine one.

Inventory systems are concurrency systems. Lock the row, verify available quantity, then write the reservation in the same transaction. It’s the simplest correct starting point.