Adding Features to Your v0 App

v0 generates UI only. Everything else needs to be built: backend API, database, authentication, state management, data fetching, form handling, file uploads, payments, email, and real-time features

The most common need is building everything behind the UI: Next.js API routes for the backend, Supabase or Prisma for the database, NextAuth for authentication, React Hook Form for form handling, Stripe for payments, and Resend for emails

Almost every SaaS app needs payment processing. Stripe is the standard — it handles credit cards, subscriptions, invoices, and payouts. The key pieces: a checkout flow for collecting payment, webhooks to update your database when payments succeed or fail, and a customer portal for managing subscriptions. v0 might generate a basic checkout page, but the webhook handling and subscription lifecycle management usually need to be built by hand.

Your app needs user accounts with secure login. The easiest options: NextAuth (for Next.js), Supabase Auth, or Clerk. These handle email/password login, social login (Google, GitHub), password resets, and session management. Don't build auth from scratch — the security implications are too complex for a first implementation.

Transactional emails — welcome emails, password resets, order confirmations — require an email service provider. Resend is the simplest to set up, SendGrid is the most established, and Amazon SES is the cheapest at scale. You'll need email templates, a sending service, and proper DNS configuration (SPF, DKIM) so your emails don't land in spam.

If a feature requires deep technical expertise (payment compliance, data privacy, real-time systems), it's faster and safer to get professional help than to iterate with AI tools. Our team adds features like these to v0 apps every week — we know the patterns and the pitfalls.