Stack guide · updated 2026-10-22
Best stack for an AI web app
Last checked Oct 2026For a developer adding LLM features to a web app: chat, generation or summaries, with users and payments.
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The stack at a glance
| Layer | Pick | Starting price | Our status | Try |
|---|---|---|---|---|
| AI editor | Cursor | Free; paid from $8/mo (Plus, Grok models only) (source) | Community-verified | Visit ↗ |
| LLM library | Vercel AI SDK | Free open-source library (source) | Not reviewed | Visit ↗ |
| LLM API | OpenRouter | Free tier (25+ free models); pay-as-you-go with 5.5% platform fee (source) | Not reviewed | Visit ↗ |
| Backend / database + auth | Supabase | Free; Pro from $25/mo (source) | Community-verified | Visit ↗ |
| Payments | Stripe | No monthly fee; 2.9% + 30¢ per domestic card transaction (source) | Not reviewed | Visit ↗ |
| Hosting | Vercel | Hobby free; Pro $20/mo (source) | Community-verified | Visit ↗ |
Each pick, and why
Cursor
Why: Repo-aware edits for the app code; Plus is $8/mo.
+ Strong tab completion and repo-aware multi-file edits
− Still breaks code without small tasks and review
Alternatives: Claude Code, Windsurf
Vercel AI SDK
Why: Free open-source TypeScript library for LLM features.
+ Free open-source TypeScript library for LLM features
− Library only: you bring models and hosting
OpenRouter
Why: One API for many models, with 25+ free models to start.
+ One API for many models, with 25+ free models
− 5.5% platform fee on pay-as-you-go
Alternatives: Google AI Studio
Supabase
Why: Postgres, auth and storage on one free tier.
+ Postgres database plus auth, storage and a free tier
− See community sources (Supabase vs Clerk) for auth trade-offs
Stripe
Why: No monthly fee; pay per transaction.
+ No monthly fee; the default payments API
− You handle sales tax/VAT yourself unless you add Stripe Tax
Alternatives: Lemon Squeezy
Vercel
Why: Free Hobby tier; first-class for Next.js.
+ Free Hobby tier; first-class for frontend and Next.js
− Pro is $20/mo per the pricing page; long-running backends fit elsewhere
Alternatives: Railway
FAQ
What is the best stack for an AI web app?
A solid default is Cursor to build, the Vercel AI SDK for LLM features, OpenRouter for model access, Supabase for database and auth, Stripe for payments and Vercel for hosting.
How much does the AI part cost?
Model usage is billed per token, so it depends on how much each user uses AI features. OpenRouter adds a 5.5% platform fee on pay-as-you-go usage and offers 25+ free models.
Do I need a separate auth service?
No. Supabase includes auth with 50,000 free monthly active users. See Best auth for SaaS for Clerk and Firebase Auth.
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How we label tools: "Tried it" means we tested it; "Community-verified" means builder feedback we cite backs it; "Not yet reviewed" means neither yet. Strengths and weaknesses come from cited community sources or official pages, not our own tests.