Many people search for a free LLM API to prototype a chatbot or test an idea before paying. Some vendors offer a real free tier, some give small starter credits, and some offer nothing free at all. Here is what our verified data shows, including what we could not confirm.
Free API options we track
| API | What is free | Limits | Status |
|---|---|---|---|
| Google Gemini API | Free of charge on eligible models: Gemini 3.8 Flash and Gemini 3.5 Flash-Lite | Per-model rate limits are shown only in Google AI Studio, not on the docs page | Verified; numeric limits not verified |
| Anthropic API | “A small amount of free credits to test the API” for new users | Amount not stated | Credit amount not verified |
| Anthropic code execution tool | 50 free hours a day per organization, then $0.05 per hour per container | Applies to the code execution tool, not model tokens | Verified |
| OpenAI API | No free tier in our data | — | not verified |
| xAI API | No free tier in our data | — | not verified |
| Perplexity API | No free tier in our data | — | not verified |
| DeepSeek API | No free tier in our data | — | not verified |
Gemini API: the clearest free tier
Google’s Gemini API is the only one in our data with a verified free tier on named models. Gemini 3.8 Flash and Gemini 3.5 Flash-Lite are free of charge on the Free tier; Gemini 4 Argon is not available on it. Two catches matter:
- Your content is used to improve Google’s products on the Free tier. Don’t send private or customer data you wouldn’t share.
- Rate limits aren’t published on the docs page. Google points to AI Studio for per-model requests and tokens per minute and per day. We don’t quote numbers we haven’t read.
When you outgrow it, Gemini 3.5 Flash-Lite’s paid rate is $0.30 input / $2.50 output per 1M tokens.
Anthropic: starter credits, not a free tier
Anthropic’s docs say new users receive a small amount of free credits. The amount isn’t stated, so treat it as a short test, not an ongoing free plan.
When “free” costs more than cheap
A free tier is great for learning and prototypes. For anything with real users, the cheapest paid models are very low. OpenAI GPT-6 Luna and Claude Haiku 5.5 start at $0.10 input / $0.50 output per 1M tokens for short prompts. Paid tiers also usually give higher rate limits and different data terms. See cheapest LLM API and model your costs in the API cost calculator.
Free chat apps are not free APIs
ChatGPT Free, Claude Free and Gemini’s free app are consumer products. They don’t give you an API key. If you just want to use AI, not build with it, see best free AI tools.
Full rates: LLM API pricing.
How we check prices
AI Stack Wise reads free-tier terms only from official vendor docs and pricing pages. If a vendor doesn’t print a number, we write “not verified” instead of estimating. Free-tier data on this page was last checked on 2026-10-19. Prices are in USD and exclude tax unless stated. See our methodology. Spotted a change? Email [email protected].