# Firebase CDN (https://www.librechat.ai/docs/configuration/cdn/firebase)
Firebase Storage integrates with Firebase Hosting's global CDN, letting you serve files stored in Firebase Storage through edge locations around the world. It is one of LibreChat's CDN-backed file storage options, alongside [CloudFront for S3](/docs/configuration/cdn/cloudfront).
A Google account and roughly 10 minutes. You'll create a Firebase project, enable Cloud Storage, register a web app to obtain credentials, then point LibreChat at it.
## Create a Firebase Project
**Open Firebase and sign in.** Go to the [Firebase website](https://firebase.google.com/), click **Get started**, and sign in with your Google account.
**Name your project.** You can reuse the same project as Google OAuth if you have one.
**Configure Google Analytics (optional).** You can disable Google Analytics for this project.
**Create the project.** Wait 20-30 seconds for provisioning to finish, then click **Continue**.
## Enable Cloud Storage
**Open All Products.** From the project dashboard, click **All Products**.
**Select Storage**, then click **Get Started**.
**Confirm the security rules.** Click **Next** to continue.
**Choose a Cloud Storage location**, then finish setup and return to the **Project Overview**.
## Register a Web App
**Add a web app.** On the Project Overview, click **+ Add app** under your project name, then choose **Web**.
**Register the app** and give it a nickname.
**Copy your `firebaseConfig` values.** Save the displayed configuration somewhere safe.
**Add the values to your `.env` file.** Map each `firebaseConfig` value to the matching variable:
```bash filename=".env"
FIREBASE_API_KEY=api_key # apiKey
FIREBASE_AUTH_DOMAIN=auth_domain # authDomain
FIREBASE_PROJECT_ID=project_id # projectId
FIREBASE_STORAGE_BUCKET=storage_bucket # storageBucket
FIREBASE_MESSAGING_SENDER_ID=messaging_sender_id # messagingSenderId
FIREBASE_APP_ID=1:your_app_id # appId
```
## Update Storage Rules
**Open Storage rules.** Return to the **Project Overview**, select **Storage**, then open the **Rules** tab.
**Allow read and write access.** Change `allow read, write: if false;` to `if true;` so it matches the rules below:
```js filename="storage.rules"
rules_version = '2';
service firebase.storage {
match /b/{bucket}/o {
match /images/{userId}/{fileName} {
allow read, write: if true;
}
}
}
```
**Publish your changes.**
## Configure LibreChat
Set `fileStrategy` to `firebase` in your `librechat.yaml` config file so LibreChat uses Firebase for file storage:
```yaml filename="librechat.yaml"
version: 1.3.5
cache: true
fileStrategy: 'firebase'
```
For more about this file, see the [librechat.yaml guide](/docs/configuration/librechat_yaml).
## Enable CORS for PNG Exports
Exporting conversations as PNG fetches images directly from Firebase Storage in the browser. Without a CORS policy that allows your domain, those requests are blocked. Skip this section if you don't export conversations as PNG.
**Create the CORS configuration file.** In a text editor, create `cors.json` and allow access from your domain:
```json filename="cors.json"
[
{
"origin": ["https://ai.example.com"],
"method": ["GET", "POST", "DELETE", "PUT"],
"maxAgeSeconds": 3600
}
]
```
**Apply the configuration.** From the directory containing `cors.json`, run the command below, replacing `` with your bucket name:
```shell
gsutil cors set cors.json gs://
```
**Verify the settings.** Retrieve the active policy and confirm it matches `cors.json`:
```shell
gsutil cors get gs://
```
**Test it.** Export a conversation as PNG from your allowed origin. If everything is configured correctly, the export succeeds without CORS errors.
Only allow CORS for trusted origins, and limit the methods and headers to what your deployment actually needs.