Click 'pay' twice when the page hangs and you shouldn't get charged twice. Here's how to make that promise — with one Redis key, a TTL, and a small race-condition guard.
If you wouldn't pour the foundation after the roof, why do we keep building UIs before we know what data lives behind them? A case for designing the schema first — not because backend matters more, but because it's the part that can't be undone.
A circuit breaker is supposed to mean the downstream is dead. Sometimes the downstream is fine — and the breaker is the problem. Three failure modes I learned the hard way, and what to do about each.