A Gemini API key lets an app call Google’s models with your own account instead of a subscription. Creating one takes about two minutes and you need nothing more than a Google account.
Create the key
- Open Google AI Studio and sign in.
- Accept the Terms of Service if this is your first visit. For a new user, AI Studio then creates a default Google Cloud project and a first API key for you.
- If no key was created, open the API Keys page and click Create API key.
- Copy the key and store it somewhere private. Treat it like a password.
If you already use Google Cloud, AI Studio does not create a project for you. Open Dashboard, then Projects, click Import projects, pick your project and confirm with Import. After that, Create API key works on the API Keys page.
If the button is greyed out with “You do not have permission to create a key in this project”, the project belongs to an organization that restricts key creation. Ask its administrator, or create a new project that is not tied to the organization.
If an older key stops working
Google changed its key types in 2026. Keys created in AI Studio since 28 May 2026 are a newer kind that Google calls auth keys, and the Gemini API now rejects standard keys that have no restrictions. Unrestricted keys that sat unused for a long time are also shown as Blocked.
If a key you made earlier suddenly fails, open it in AI Studio, choose Add restrictions, then Restrict to Gemini API only and Restrict key. Or simply create a new key.
Which models are free
On the free tier, Google lists these models as free of charge:
| Model | Free tier | Accepts images |
|---|---|---|
| Gemini 3.1 Flash-Lite | Yes | Yes |
| Gemini 3.5 Flash-Lite | Yes | Yes |
| Gemini 3.6 Flash | Yes | Yes |
| Gemini 3.8 Flash | Yes | Yes |
| Gemini 3.1 Pro (preview) | No | Yes |
| Gemini 4 Argon | No | Yes |
Gemini 4 Argon, released in October 2026, is paid only. If you want the newest free model on the same key, use Gemini 3.8 Flash. See is the Gemini 4 Argon API free? for its price.
One more difference between the tiers: on the free tier, Google may use your prompts and answers to improve its products. The paid tier does not. Keep that in mind before you send anything private.
What the free tier limits
Google does not publish one number that applies to everyone. Three things are worth knowing:
- Limits are counted three ways: requests per minute, input tokens per minute and requests per day. Going over any one of them returns an error until it resets.
- Limits belong to the project, not to the key. Making a second key in the same project does not double your allowance.
- The daily count resets at midnight Pacific time.
Your own numbers are shown in AI Studio, per model. Check them there before you rely on a model for something long: the lighter Flash-Lite models usually allow more requests than the larger ones.
Which model to pick
For everyday questions, start with Gemini 3.5 Flash-Lite, the fastest and most cost-effective of the 3.5 models. Move up to Gemini 3.6 Flash or Gemini 3.8 Flash when an answer needs more reasoning. All of them accept images, so charts and diagrams work too.
Keep the key safe
- Do not paste it into chat messages, screenshots, public repositories or shared notes.
- Keep the Restrict to Gemini API only restriction on, so a leaked key cannot be used for other Google services.
- If a key leaks, create a new one, switch to it, then disable the old one.
Common questions
Is the Gemini API free? Yes, for the Flash and Flash-Lite models in the table above, within the limits AI Studio shows for your project. Gemini 4 Argon and Gemini 3.1 Pro are not on the free tier.
Why does my key say “Blocked”? It is most likely an old unrestricted key. Add the Gemini API restriction or create a new key.
Using the key in LuciQA
LuciQA is a free desktop app that answers questions about what is on your screen with the provider you choose. Open Settings, pick Google Gemini, paste the key, choose a model and save. Your key is kept in the operating system’s secure storage, and requests go straight from your computer to Google.
The Gemini setup guide has the same steps with the current model list, and the free AI APIs comparison shows the other providers that have a free tier.