The fastest way to build a web app with AI is to ship one narrow, complete user journey before expanding the feature list. Define the user, the single job, the input, the output, and the conditions that make the result acceptable. Speed comes from fewer open decisions, not more generated code.
Give the agent a small project brief: chosen stack, repository rules, data entities, page states, external services, and commands for linting, tests, and builds. Ask for a plan that identifies the riskiest dependency first. Implement a vertical slice that crosses the interface, server logic, and persistence layer. Use seed data and a local or preview environment so every change can be exercised immediately. Keep optional integrations behind adapters or flags until the core flow works.
Do not measure progress by files created. Track whether a new user can reach the promised outcome, whether invalid inputs fail clearly, and whether the app can be rebuilt from documented steps. If authentication, payments, or sensitive data are involved, slow down for threat review and provider-specific verification.
A useful first release may be plain, but it should be coherent. Freeze the working path, record remaining risks, and give the next agent task one observable outcome. That creates repeatable velocity instead of a fast prototype followed by expensive reconstruction.
