Free LLM API Key: 8 Signup Paths and Limits (2026)

A free LLM API key is useful for prototypes, scripts, and model comparisons, but “free” does not always mean renewable or production-safe.

Check these four conditions before signing up

Before signing up, check these four failure points:

A recurring quota renews; a trial credit runs down or expires. Treat every number below as a dated snapshot and confirm it in the provider’s live limits panel.

Exact limits can change, and a provider’s model catalog may contain entries unavailable to your account.

Recurring quota or trial credit

Google AI Studio, Groq, Cloudflare Workers AI, and selected Z.ai routes provide ongoing access in the cited provider documentation. Cohere’s trial key, Hugging Face’s small inference credit, and signup balances are different: they run down.

Card and phone requirements

No-card does not mean no verification. NVIDIA NIM’s signup may include phone verification; some Mistral accounts also request SMS verification. Google AI Studio and Groq are usually lower-friction starting points, but requirements vary by account and region.

Data use and commercial restrictions

Google’s free-tier billing documentation and Mistral’s pricing documentation explain that data-use conditions can differ from paid access. Read the current provider terms before sending private or customer data.

OpenAI-compatible endpoint or provider-native API

An OpenAI-compatible base URL makes a key easy to test with familiar SDKs, but compatibility is not identical behavior. Model IDs, streaming, tool calling, context limits, and error formats can still differ. Google AI Studio and Cloudflare Workers AI use provider-specific request formats; Groq, OpenRouter, Mistral, and other providers expose OpenAI-style endpoints in their documentation.

Provider-by-provider signup routes

The links below point to provider consoles or official developer pages, not shared-key repositories. Create your own key; never copy a key posted in a README, video, or comment.

Google AI Studio: easiest multimodal starter

Signup path

1. Open Google AI Studio.
2. Sign in with a Google account.
3. Open the API-key area and choose Create API key.
4. Copy the key once and store it in an environment variable.

The free route is useful for multimodal experiments: Google documents Gemini models with text, image, audio, and video input, and the listed Flash variants can have context windows up to 1 million tokens. Google directs users to the AI Studio quota panel because limits vary by model and account.

Use it first when: you need long context or multimodal input without adding a card. Watch for: current data-use and regional API-client terms.

Groq: the simplest OpenAI-compatible speed path

Signup path

1. Open the Groq Console.
2. Create an account or use supported single sign-on.
3. Open API Keys.
4. Create a key and copy it immediately.

The documented endpoint is https://api.groq.com/openai/v1. Groq’s rate-limit documentation lists model-specific RPM and daily limits; check that page instead of hard-coding a number from an old directory. Groq has retired models before.

Use it first when: you want a familiar OpenAI SDK and fast interactive responses. Watch for: changing model IDs and per-model daily caps.

OpenRouter: one key for rotating free models

Signup path

1. Open OpenRouter.
2. Sign in with a supported account.
3. Open the Keys page.
4. Create a key, then select a model marked with the :free suffix in the model catalog.

OpenRouter’s endpoint is https://openrouter.ai/api/v1. One key can reach a changing set of upstream models, but availability and provider routing can change. Check the limits documentation before assuming a request allowance.

Use it first when: you are comparing models and can tolerate a rotating catalog. Watch for: a free model disappearing, regional 403 responses, and platform rules against reselling or building a competing proxy.

NVIDIA NIM: broad catalog, phone verification

Signup path

1. Open NVIDIA’s API catalog.
2. Create or sign in to an NVIDIA Developer account.
3. Complete phone verification if requested.
4. Open a callable model page and choose Get API Key.
5. Copy the model ID exactly as displayed.

The documented OpenAI-style endpoint is https://integrate.api.nvidia.com/v1. NVIDIA’s free route is intended for evaluation, and model availability can differ between the catalog and callable endpoints. Check the model page’s current limit before integrating it.

Use it first when: you need to test many open-weight models. Watch for: phone verification, model availability, and the evaluation-only boundary.

Mistral AI: a large allowance with low throughput

Signup path

1. Open the Mistral developer console.
2. Create an account and complete any requested verification.
3. Select the free experimentation mode.
4. Create an API key in the API-key section.

Mistral’s endpoint is https://api.mistral.ai/v1. Mistral documents free credits shared across its products and directs users to the account Limits page for current values.

Use it first when: you need multilingual or coding models for a low-concurrency project. Watch for: shared credits, throughput limits, and the free-mode data-use setting.

Cloudflare Workers AI: daily Neurons allocation

Signup path

1. Create a Cloudflare account.
2. Open Workers AI in the dashboard.
3. Create an API token with the Workers AI permissions shown in the dashboard.
4. Use your account ID and token with the Workers AI endpoint.

The Workers AI pricing page documents a 10,000-Neuron daily free allocation shared across the account and reset at 00:00 UTC. Neurons are not tokens: model choice changes consumption. Some models require a paid Workers plan.

Use it first when: your application already runs on Cloudflare. Watch for: account-wide quota sharing and the non-token billing unit.

GitHub Models: useful for prototypes, not a free production backend

Signup path

1. Sign in to GitHub Models.
2. Choose a model or open the playground.
3. Create the GitHub personal access token required by the current Models instructions, or use the playground’s generated access path.
4. Check the model’s current rate limit before wiring it into an application.

GitHub’s model access is convenient for testing, but free-tier quotas depend on account and model and may be small. Treat it as a development route, not unlimited access to premium models.

Use it first when: your code and experiments already live in GitHub. Watch for: account-dependent limits and prototype-only restrictions.

Z.ai: free GLM access with one-request concurrency

Signup path

1. Open Z.ai’s API documentation.
2. Register for the developer platform.
3. Create a key in the user center.
4. Select a current Flash model and use the international endpoint if it is appropriate for your account.

The documented endpoints include https://api.z.ai/api/paas/v4 and the regional https://open.bigmodel.cn/api/paas/v4. Z.ai’s pricing page lists selected Flash models at zero input and output price; the free route is limited to one concurrent request. That suits sequential scripts but not parallel agents.

Use it first when: you need Chinese/English work or want to test GLM. Watch for: one-request concurrency, regional endpoint differences, and model retirement notices.

Test the key without leaking it

Do not paste a key into source code or shell history. Store it as an environment variable, then make one small request:

export LLM_API_KEY="paste-your-own-key-here"

curl https://api.groq.com/openai/v1/chat/completions \
  -H "Authorization: Bearer $LLM_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "llama-3.3-70b-versatile",
    "messages": [{"role":"user","content":"Reply with one word: ready"}],
    "max_tokens": 8
  }'

Change the base URL and model ID for another OpenAI-compatible provider. If the response fails:

1. 401: the key is missing, malformed, revoked, or copied with extra characters.
2. 403: the model, region, account, or use case is not permitted.
3. 404: the base URL or model ID is wrong.
4. 429: you hit a request, token, or concurrency limit. Slow down; do not launch automatic retries in a tight loop.

A successful test proves one model answered once, not that quotas renew, production use is permitted, or all models behave identically.

Choose by workload, not by the word “free”

Where free API keys stop being a sensible choice

A free key is a poor fit for a production service that needs an SLA, predictable throughput, or customer-data guarantees. It is also a poor fit for a public proxy: a provider may prohibit reselling access, and a shared key can be revoked without warning.

Create the key yourself, keep it server-side, rotate it if it appears in logs, and never use a key copied from a public repository. A public key may already be exhausted or compromised, and using it can expose prompts to an unknown intermediary.

“I'm gonna kill someone why TF do people advertise free llm api only to not actually provide it and instead just respond with rate limit error before you can even send one prompt?” — @bunny3111039587, a real user discussing free LLM API access.

Treat a free endpoint as an experiment with a stop condition, not as a substitute for paid capacity.

Free LLM API key FAQ

Can I get a free LLM API key without a credit card or phone number?

Often, yes. Google AI Studio, Groq, and OpenRouter are commonly documented as email-based routes, while NVIDIA NIM and some Mistral accounts may request phone verification. Requirements vary by region and account, so check the current signup screen.

Can I get a free GPT API key?

You may get free access to some GPT-family models through a hosted platform or developer program, but that is not the same as a permanently free OpenAI API key. Check whether the route is a trial, prototype-only access, or a third-party gateway.

Can I get a free Claude API key?

Do not assume a generally available, permanently free first-party Claude API key. Some gateways expose Claude-compatible routes, but they may require credits, have separate terms, or use an Anthropic-compatible endpoint.

Do free API keys expire?

Recurring tiers may not have a stated expiry, while trial credits expire or run out. A provider can also revoke a key, retire a model, change a quota, or remove a free route. Record when you checked the provider’s limits.

Can I use a free LLM API key commercially?

Not automatically. Trial and evaluation routes may prohibit production or commercial use, and model providers can attach additional restrictions. Read the current provider and model terms before shipping a commercial feature.

What should I do after a 429 error?

Read the response headers and quota panel, then reduce concurrency, add exponential backoff, shorten requests, or switch to a permitted fallback. Do not rotate through other people’s keys or hammer the same endpoint.

The practical answer to “which LLM gives a free API key?” is to start with Google AI Studio for multimodal work, Groq for an OpenAI-style prototype, or OpenRouter for model breadth, then move to paid or self-hosted capacity when the project needs predictable throughput or private prompts.