How to build an AI app entirely on free tiers (the 2026 stack)
September 6, 2026 · 7 min read · by devAge
You can build and launch a real AI app in 2026 without paying for anything until you have actual users. The trick is knowing which free tiers are genuinely free-to-run (not just a trial) — and where each one quietly ends. Here's a verified starting stack.
Foundations
- Database — Supabase or Neon. Supabase bundles Postgres, auth, storage and realtime on one free project (the catch: projects auto-pause after 7 days idle). Neon is serverless Postgres that scales to zero with no idle pause.
- Auth — Clerk or Firebase Auth. Clerk gives you drop-in UI free to ~10k monthly users; Firebase Auth is free and generous.
- Hosting — Cloudflare Pages/Workers or Vercel. Cloudflare's free tier is generous with no commercial restriction; Vercel is unbeatable for Next.js but its Hobby tier is non-commercial, so budget for Pro once you monetize.
The AI layer — don't default to the priciest model
The single biggest free-tier win is picking the right model for the job. For most tasks — classification, extraction, chat — a fast cheap model is plenty:
- Google AI Studio (Gemini Flash) — ~1,500 requests/day free, no card. Note: free inputs may train Google's models, so don't send sensitive data.
- Groq — the fastest inference, ~1,000 requests/day free per model.
- OpenRouter — one API, many models, with free variants you can route cheap tasks to.
Reserve premium reasoning models for genuinely hard reasoning or coding — not for simple classification, where they just cost more for the same result.
Feature APIs that are actually free to start
- Speech-to-text — AssemblyAI ($50 credit, no expiry, no card) or Deepgram ($200 signup credit).
- Email — Resend (~3,000/mo free) for transactional mail.
- Push — Firebase Cloud Messaging, fully free and unlimited.
Where “free” ends
The honest part most lists skip: image generation is mostly one-time credits, not an ongoing free tier (Stability, Fal). And your whole stack is free to build and test — the first real cost usually shows up at the tightest tier, often the database once you cross its row/MAU limits.