How can a startup move fast without destroying code quality?

The trick is to be explicit about where you accept shortcuts and where you demand rigor. Moving fast does not mean ignoring tests, reviews, or documentation everywhere; it means picking the right places to relax standards temporarily. Protect the foundation of your product such as authentication, billing, and core business logic, and be more flexible in experimental areas like early prototypes or marketing pages. Encourage small, frequent releases so problems are easier to spot and fix. Make time regularly to clean up the most painful shortcuts instead of waiting until the codebase feels unmanageable.