A working demo proves an idea. A product must also survive confusing input, slow networks, repeated requests, changing requirements, and users returning months later.
Start with the critical path #
Identify the smallest end-to-end journey that creates value. Build and instrument that path before expanding the feature list. It reveals bad assumptions earlier than isolated frontend or backend work.
Model the domain explicitly #
Names such as Deal, Wishlist, Subscription, and PriceAlert should mean the same thing in the UI, API, and database. Clear domain boundaries reduce translation bugs and make later features easier to place.
Make operations boring #
Validate configuration at startup, apply database migrations predictably, expose health checks, and log useful context without leaking secrets. Add a rollback plan before the risky release, not after it.
Shipping is a loop: release a narrow slice, observe real behavior, remove friction, and repeat. Reliability is part of the user experience.