Get an AI API key: free tiers compared

Four of the six major AI APIs can be used without paying: Gemini, Groq, OpenRouter and Mistral. OpenAI and Claude run on prepaid credit. Each guide shows how to create the key, what it costs and how to keep it safe.

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Free tiers and key details at a glance

Provider	Can you use it free?	Card needed	Key starts with	Environment variable
Google Gemini	Yes: a free tier for several Gemini models, within rate limits	No	`AQ.` (new keys) or `AIza` (older)	`GEMINI_API_KEY`
Groq	Yes: a Free tier (e.g. gpt-oss at 1,000 requests a day)	Only to upgrade	`gsk_`	`GROQ_API_KEY`
OpenRouter	Yes: `:free` models, 50 requests a day (1,000 after buying $10 of credits)	Not for free models	`sk-or-v1-`	`OPENROUTER_API_KEY`
Mistral	Yes: Free mode (your data may be used for training unless you opt out)	No (Free mode)	Not documented	`MISTRAL_API_KEY`
OpenAI	No: prepaid credit, $5 minimum	Yes	`sk-`	`OPENAI_API_KEY`
Anthropic (Claude)	No: prepaid credits (new users may get a small test credit)	Yes	`sk-ant-`	`ANTHROPIC_API_KEY`

Checked 2026-10-11 against each provider’s own pages · details and sources in each guide

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How these tools fit together

“Free” means different things at each provider, so the table compares like with like. Gemini, Groq and Mistral have free tiers or modes with rate limits; OpenRouter offers models marked :free with a daily allowance; OpenAI and Anthropic bill prepaid credit from the first request. Free tiers can also change what happens to your data: Google says free-tier content is used to improve its products, and Mistral’s Free mode may use your data for training unless you opt out. Each guide quotes the provider’s own terms with the date we checked them.

Every guide follows the same steps: where to create the key, what you pay, which environment variable the official SDKs read, a curl example taken from the provider’s docs, and how to keep the key safe. Treat a key like a password: keep it in an environment variable or a secrets manager, never in code you commit, and delete it straight away if it leaks.

To test a key without sharing it, the API key checker sends it from your browser straight to the provider you choose, using a free request that generates no tokens. It never reaches this site’s server. With a working key you can try models in the Gemini playground or get official token counts in the token counter.

FAQ

Questions people ask

Which AI APIs can I use for free?

Google Gemini (free tier for several models, no card), Groq (Free tier, a payment method only to upgrade), OpenRouter (models marked :free, 50 requests a day, 1,000 after buying $10 of credits) and Mistral (Free mode, no card). All have rate limits. OpenAI and Anthropic need prepaid credit, as their guides explain.

Do I need a credit card to get an AI API key?

Not for Gemini, Groq’s Free tier, OpenRouter’s free models or Mistral’s Free mode. OpenAI requires prepaid credit with a $5 minimum, and Claude’s API runs on prepaid credits, so both need a payment method before real use.

Is Groq the same as Grok?

No. Groq is a company that runs open models such as gpt-oss and Qwen on its own LPU chips, sold through GroqCloud. Grok is xAI’s chatbot and model family, with its own separate API. A Groq key won’t work with xAI’s API, and the other way round.

Is it safe to test my API key on a website?

Only if the key goes straight to the provider. Our API key checker sends it from your browser directly to the provider you pick, in a request header, and never stores it or sends it to this site. If you’d rather not paste it anywhere, each guide shows a curl command to test it from your terminal.