Building real featuresAdding a database without regretGet the shape right early — data outlives code.Building real featuresBuilding an API others can useConsistency matters more than cleverness.Building real featuresAuthentication, safelyThe one place where "don't build it yourself" is a rule, not advice.Building real featuresKeeping keys out of your codeDo this on day one. Retrofitting it means rotating everything.Building real featuresSecurity, the parts that actually get youFive holes account for most real incidents in small apps.Building real featuresTaking paymentsNever touch a card number. Everything else is manageable.Building real featuresSending email that arrivesGetting it sent is easy. Getting it delivered is the work.Building real featuresHandling file uploadsA form where strangers write files onto your infrastructure.Building real featuresHandling other people's dataCollect less, keep it less long, and know where it is.