Vibe Coding for SaaS MVPs Checklist

Vibe coding accelerates SaaS MVP development — but speed without structure produces a fast mess. This checklist keeps your build focused, your scope contained, and your output shippable. Run through it before you start, during the build, and before you hand your MVP to first users.

✅ Phase 1: Before You Start Coding

• → Define the activation event — the single action that proves your core value to a user. Everything in the MVP exists to get users to this moment.
• → Write the five-screen scope — list the exact screens your MVP needs. If you cannot name them, you are not ready to build. Cut anything that is not required for the activation event.
• → Set a hard deadline — 2 weeks for a solo founder, 4 weeks maximum. A vibe coding MVP that takes 3 months is not a vibe coding MVP.
• → Choose your stack before session 1 — pick one frontend framework, one backend, one database. Do not let the AI suggest alternatives mid-build; context switching costs days.
• → Write your master prompt — describe your product, tech stack, target user, and the activation event in 200 words. Paste this at the start of every AI coding session to maintain context.
• → Set up auth before anything else — auth retrofitted later is a week of work. Use Clerk, Supabase Auth, or Auth.js from session 1.
• → Create a feature parking lot — a text file or Notion page for ideas that come up during the build. Every "what if we also" idea goes there, not into the codebase.

✅ Phase 2: During the Build

• → Commit after every working feature — never let the AI rewrite more than you can recover in 10 minutes. Commit early, commit often, use descriptive messages.
• → Test the happy path manually after every session — AI-generated code often breaks adjacent features silently. Walk the core user flow after every major change.
• → Keep sessions under 90 minutes — AI context degrades in long sessions. Start a fresh session with your master prompt rather than continuing a session that has gone stale.
• → Do not add new features until existing ones work end-to-end — the AI will happily scaffold new screens while previous screens are broken. Keep the build vertical, not horizontal.
• → Review generated code before merging — read every significant function. You are responsible for what ships, and AI hallucinates edge cases silently.
• → Use real data from day one — seed your database with realistic test data immediately. UIs built against empty states ship with empty-state bugs.
• → Log errors explicitly — add a simple error boundary and a console.error wrapper early. Debugging a vibe-coded app without error visibility is extremely slow.

✅ Phase 3: Before You Ship to First Users

• → Walk the full signup-to-activation-event flow as a new user — use an incognito window, a fresh account, no pre-loaded data. This is what your users will experience.
• → Check mobile layout — even B2B SaaS gets first visits on mobile. Broken layout kills trust before the user sees the product.
• → Verify environment variables are set in production — the most common vibe coding ship failure. API keys, database URLs, auth secrets — confirm all are set in your hosting environment.
• → Add basic error handling for empty states — every list that can be empty needs an empty state. Every form that can fail needs a failure message.
• → Test signup with a real email address you control — confirm the confirmation email arrives, the link works, and the user lands on the right page.
• → Set up a way to receive user feedback — a Tally form, a feedback widget, or a mailto link. You need feedback before you can iterate.
• → Know your rollback plan — if something breaks after you share the link, what do you do? A rollback to a known-good commit should take under 5 minutes.

What to Do Next

Run Phase 1 today if you have not started building. If you are mid-build, run Phase 2 retrospectively — identify what you skipped and address the highest-risk gaps before your next session. If you are about to share the link with your first users, run Phase 3 in order and do not skip the incognito signup test. That test finds 80% of the issues your first user will encounter.