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Developers & Practitioners

Securing Your Gemini and Google API Keys

May 21, 2026

Leonid Yankulin<br>Senior Developer Relations Engineer

Today, AI services rely heavily on API keys. To run AI agents, users provide API keys that signify paid tokens, subscriptions, or paid accounts. While API keys are easy to use, it is just as easy to use them unsafely. The result of a hijacked key is a compromised environment that is misused or abused by perpetrators.

I decided to write this blog post after seeing a thread in the r/googlecloud subreddit asking for a tutorial so users can go and protect themselves. In this post, you will find a few simple steps you can take to reduce your risks and improve the security of API keys created by Google .

You use Google API keys to access Gemini and other AI Google products as well as Google Cloud APIs. In fact, a Gemini API key is actually a standard Google API key behind the scenes. While I will be focusing on Google API key security, you can apply some of these recommendations to API keys and product tokens created elsewhere.

Step 1: Generate a New API Key

Regardless of where you start, you end up creating a new API key in one of Google Cloud projects. You probably will use Credentials under the "APIs & Services" menu in the Cloud console.

Or you may use gcloud services api-keys create command instead. Or there is some other interface which will create a new Google Cloud API key. Regardless of the path and the interface, you need to do the following:

Create the key in a stand alone project that is not used for any other purpose.

Restrict API access and client applications for the new API key.

These steps limit the potential reach of the key and greatly simplify troubleshooting activities when something goes wrong.

API Restrictions

API restrictions specify what services you can access using the key. DO NOT create unrestricted keys, as a stolen key would grant an attacker access to any available service at your expense.

ALWAYS limit the list of the services this key is used for to reduce the potential damage (a.k.a. blast radius) in event the key is hijacked or exposed. Be attentive when you use indirect UI to create a new key. For example, creating an API key in Firebase restricts the use to 24 APIs including Datastore, Firestore, Cloud SQL Admin and others.

If you use Firebase to store your website you probably will not use most of them. When you create an API key to use with AI Studio, restrict it to only "Gemini API".

Attention points:

By default a new API key is created without restriction.

If you search for an API that you want to select but it is missing, this API is probably not enabled in the Google Cloud project that you use. Go to the API Library in your Cloud console, find the API by name and enable it first.

You can do all actions using the Cloud console or gcloud CLI. Other interfaces (e.g. Firebase) may not provide you with access to all parameters of the API keys

Application Restrictions

Similar to API restrictions that limit what services your key can be used for, Application Restrictions limit the applications which can use the key. For example, if you create an API key only for use with Google AI Studio, setting up the application restrictions to the website "https://aistudio.google.com/" will prevent using your key by automations that utilize Gemini and consume a high volume of tokens at scale.

You can set up one or more restrictions of one of the following types:

Website /Web application using the list of URLs

Services using the list of IPv4 or IPv6 address or a subnet masks

iOS applications using the list of Bundle IDs

Android applications using the list of pairs of the package name and certificate fingerprint

Note that you can restrict the key to a single application type only. Create a designated API key for each application type. Having a key per application type helps when observing the key usage and investigating potentially compromised keys.

Step 2: Store API key

I want to reiterate that the API key is not paired with your identity. ANYONE can use it. So, storing the key securely is as important as restricting the key use in Step 1.

The rule is simple: NEVER EVER store the key where it can be easily seen.

If you use an API key in your application , store it in Secret Manager or a similar secret management service. Secret Manager allows you to inject your API key into Cloud Run and GKE environments easily. However, to elevate the key protection you may want to read the key in your code instead. See documentation for an example.

If you use an API key with an external application that asks you to type in the key, take extra steps to explore how the application manages your key. You would need to find out how the key is stored and how it is used in the requests. For Web applications, you may use browser developer tools to inspect...