GuideAug 13, 2026~8 min · intermediate

Ship a SaaS in 24h with Claude Code

Not a throwaway prototype: a live SaaS, with auth, database and payments, in a day. Here's the hour-by-hour plan, what Claude Code truly accelerates, and the shortcuts that cost you later.

StackClaude CodeNext.jsPrismaStripeVercel

The 24h plan

Speed doesn’t come from typing faster, it comes from not hesitating. The breakdown I follow, in blocks, to never get stuck.

h 0-2scaffold, repo, CLAUDE.md, empty deploy live

h 2-8data model, auth, core CRUD

h 8-16the key screens, the UI, the edge cases

h 16-22Stripe payments, emails, polish

h 22-24tests, basic security, go live

Lay the foundations

First rule: deploy an empty app live within the first hour. A pipeline that works early avoids the classic “works locally but not in prod” at 11pm.

shellBASHCopy

# heure 0-2 : poser les fondations, vite
$ npx create-next-app@latest shop --ts --tailwind --app
$ cd shop && git init && gh repo create --private --source=.
# ecrire le CLAUDE.md AVANT de coder : stack, conventions, commandes

Good reflex

Write the CLAUDE.md before the first line of code. It’s what keeps Claude aligned with your stack for 24h — I make it the core of the basics of Claude Code.

Build in loops

You move feature by feature, letting Claude propose a plan then edit. The key to speed: one scoped task at a time, and you have it run the tests at each step.

sessionBASHCopy

> lis le CLAUDE.md. On construit un SaaS de gestion de factures.
> Etape 1 : schema Prisma (User, Org, Invoice) + auth par email/mot de passe.
# Claude propose le schema, les migrations, les routes. Tu relis chaque diff.
> lance prisma migrate et les tests

What breaks when you rush

Skipped security

Unprotected API routes, hardcoded secrets: the shortcut that comes back to bite you. Keep 1h for it.

Zero tests

Without tests, each new feature silently breaks the previous one. Even a smoke test beats nothing.

Data debt

A sloppy schema at hour 3 is paid at hour 20. Spend 20 more minutes on the model.

Scope creep

In 24h, one value proposition only. Everything else waits for tomorrow.

Careful

The biggest risk isn't Claude, it's you accepting diffs without reading them to go faster. The classic mistakes are in the common mistakes with Claude Code.

Sources & further reading

01Next.js — create-next-app CLIEvery scaffold option — TypeScript, Tailwind, App Router, and the --agents-md flag that generates CLAUDE.md.↗02Claude Code — Best practicesHow to write a short, useful CLAUDE.md, and why you should give Claude a check it can run on its own.↗03Better Auth — InstallationEmail/password auth in a few steps: secret, instance, generated schema, catch-all /api/auth/* route.↗04Prisma — Migrate in development and productionThe distinction that saves you at hour 22: migrate dev locally, migrate deploy in production — never the reverse.↗05Stripe — Checkout quickstartThe hosted payment page: server-side session, prices never in the client, test cards.↗06Stripe — WebhooksVerify the signature, return 2xx fast, and handle duplicates: events arrive out of order and get replayed.↗07Vercel — Deploying to VercelGit, CLI or drop: the ways to go live, and the preview / production split from hour 1.↗

In short

A SaaS in 24h is possible because Claude Code removes hesitation, not rigor. Solid foundations early, short loops, and one hour kept for security and tests: the rest is execution.

Claude Code docs ↗