Get started using App Check with reCAPTCHA Enterprise in web apps

This page shows you how to enable App Check in a web app, using the reCAPTCHA Enterprise provider. When you enable App Check , you help ensure that only your app can access your project's backend resources. See an Overview of this feature.

Note that App Check uses reCAPTCHA Enterprise score-based site keys, which make it invisible to users. The reCAPTCHA Enterprise provider will not require users to solve a challenge at any time.

If your use case requires reCAPTCHA Enterprise features not implemented by App Check , or if you want to use App Check with your own custom provider, see Implement a custom App Check provider .

1. Set up your Firebase project

1. Add Firebase to your JavaScript project if you haven't already done so.

2. Open the reCAPTCHA Enterprise section of the Cloud console and do the following:

   1. If you're prompted to enable the reCAPTCHA Enterprise API, do so.
   2. Create a Website-type key. You will need to specify domains on which you host your web app. Leave the "Use checkbox challenge" option unselected.

3. Register your apps to use App Check with the reCAPTCHA Enterprise provider in the App Check section of the Firebase console. You will need to provide the site key you got in the previous step.

   You usually need to register all of your project's apps, because once you enable enforcement for a Firebase product, only registered apps will be able to access the product's backend resources.

4. Optional: In the app registration settings, set a custom time-to-live (TTL) for App Check tokens issued by the provider. You can set the TTL to any value between 30 minutes and 7 days. When changing this value, be aware of the following tradeoffs:

   • Security: Shorter TTLs provide stronger security, because it reduces the window in which a leaked or intercepted token can be abused by an attacker.
   • Performance: Shorter TTLs mean your app will perform attestation more frequently. Because the app attestation process adds latency to network requests every time it's performed, a short TTL can impact the performance of your app.
   • Quota and cost: Shorter TTLs and frequent re-attestation deplete your quota faster, and for paid services, potentially cost more. See Quotas & limits .

   The default TTL of 1 hour is reasonable for most apps. Note that the App Check library refreshes tokens at approximately half the TTL duration.