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Building AI Apps with Free APIs: A Developer's Handbook
February 10, 2026 · Free AI · API, Development, Tutorial, LLM
Building AI Apps with Free APIs
You don’t need a budget to build AI-powered applications. Here’s how to use free-tier APIs to build real products.
Setting Up Your API Keys
OpenAI
Sign up at platform.openai.com and navigate to API keys. New accounts get free credits. Use GPT-4o Mini for the best cost-to-quality ratio.
Google Gemini
Google AI Studio is the most generous. You get 1,500 free requests per day with Gemini 1.5 Pro — no credit card required.
Groq
Groq offers blazing-fast inference. Their free tier supports LLaMA 3, Mixtral, and Gemma. Sign up at console.groq.com.
Anthropic Claude
Anthropic gives new developers free credits for Claude. Use Claude 3 Haiku for the fastest, cheapest option.
Architecture Patterns
Streaming Responses
Use the Vercel AI SDK for streaming:
import { generateText } from 'ai';
import { openai } from '@ai-sdk/openai';
const { text } = await generateText({
model: openai('gpt-4o-mini'),
prompt: 'Explain quantum computing simply',
});RAG (Retrieval-Augmented Generation)
LlamaIndex makes RAG simple. Index your documents, then query them with natural language.
LangChain offers more flexibility with chains and agents for complex workflows.
Vector Databases (Free Tiers)
- Pinecone — Free starter tier
- Supabase — pgvector built-in, generous free tier
- Qdrant — Open-source, self-hostable
Speech and Vision
Speech-to-Text
OpenAI Whisper is completely free and open-source. Run it locally or use the API.
Image Generation
Stable Diffusion via ComfyUI gives you unlimited free image generation locally.
Image Understanding
CLIP by OpenAI lets you search and classify images using natural language — completely free.
Deployment
Where to Host
- Vercel — Best for Next.js apps, generous free tier
- Railway — $5/month free credits for backends
- Cloudflare Workers — 100K free requests/day
Monitoring
Use Helicone (free tier) to monitor your LLM API usage, costs, and latency.
Complete Stack Example
Here’s a production-ready stack using only free tiers:
| Layer | Tool | Free Tier |
|---|---|---|
| Frontend | Next.js on Vercel | Unlimited |
| LLM API | Google AI Studio | 1,500 req/day |
| Embeddings | Hugging Face | Rate limited |
| Vector DB | Supabase | 500MB |
| Auth | Clerk | 10K MAU |
| Speech | Whisper | Unlimited (local) |
Key Takeaways
- Start with Google AI Studio for the best free LLM access
- Use Vercel AI SDK for streaming UI
- Deploy on Vercel for zero-config hosting
- Monitor with Helicone to track costs before they happen
- Keep Ollama installed for offline development
The tools are free. The only cost is your time.