Your contact form takes a name, an email, and a message. Three fields. Two of them can take over your mail server if you let them. A short tour of an attack that's older than I am, and how I found it in code I'd just shipped.
A classroom is fine until the teacher tries to hear thirty questions at once. Scaling a real-time edtech platform from a small cohort to many thousands of concurrent learners taught me which decisions to make on day one — and which mistakes I made on day fifty.
You can't shut the kitchen down for six weeks while you remodel — there are still customers eating. Here's how I replaced a legacy CRM piece-by-piece, kept the lights on, and slept at night.
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.