# Firebase Cloud Messaging (FCM) (/platform/integrations/push/fcm)

Learn how to use the Firebase Cloud Messaging (FCM) provider to send push notifications using Novu

import { Accordion, Accordions } from 'fumadocs-ui/components/accordion';

This guide explains the process of configuring and using FCM with Novu, from getting your credentials to sending your first notification.

<Callout> Novu uses FCM version V1</Callout>

## Step 1: Generate your service account key from Firebase

Get your project's service account credentials from the Firebase Console.

1. Log in to the <a href="https://console.firebase.google.com/" target="_blank" rel="noopener noreferrer">Firebase console</a>.
2. Create a new Firebase project or select an existing project.
   ![Select Firebase Project](/images/channels-and-providers/push/select-firebase-project.png)
3. Click the gear icon ⚙️ next to **Project Overview**.
4. Select **Project settings**.
   ![Firebase Project Settings](/images/channels-and-providers/push/firebase-project-settings.png)
5. Click the **Service accounts** tab.
6. Click the **Generate new private key** button. A confirmation menu appears.
   ![Firebase Service Accounts](/images/channels-and-providers/push/firebase-service-accounts.png)
7. Click **Generate key** to download a JSON file containing your credentials.
   ![Firebase generate private key confirmation dialog](/images/channels-and-providers/push/confirmation-menu.png)
8. Open the downloaded JSON file and ensure it contains these fields:
   ```json
   {
     "type": "service_account",
     "project_id": "PROJECT_ID",
     "private_key_id": "PRIVATE_KEY_ID",
     "private_key": "PRIVATE_KEY",
     "client_email": "FIREBASE_ADMIN_SDK_EMAIL",
     "client_id": "CLIENT_ID",
     "auth_uri": "https://accounts.google.com/o/oauth2/auth",
     "token_uri": "https://oauth2.googleapis.com/token",
     "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
     "client_x509_cert_url": "CLIENT_X509_CERT_URL"
   }
   ```

## Step 2: Connect FCM to Novu

Add the credentials to your FCM integration in the Novu dashboard.

1. Log in to the Novu dashboard.
2. Navigate to the **Integration Store**.
3. Click **Connect provider**.
4. Click the **Push** tab, then select **Firebase Cloud Messaging (FCM)**.
5. Open the JSON file you downloaded from Firebase in [Step 1](/platform/integrations/push/fcm#step-1-generate-your-service-account-key-from-firebase).
6. Copy the entire content of the JSON file and paste it into the **Service Account** field in the FCM integration modal.
   ![FCM integration](/images/channels-and-providers/push/fcm-integration.png)
7. Click **Create Integration** to save the integration.

## Step 3: Register a subscriber's device token

Before Novu can send a push notification to your subscriber, you must associate their device's unique push token with their Novu subscriber profile.

You can do this by making an API call to [update the subscriber's credentials](/api-reference/subscribers/update-provider-credentials).

<Tabs items={['Node.js', 'cURL']}>
  <Tab value="Node.js">
    ```typescript
    import { Novu } from "@novu/api";
    import { ChatOrPushProviderEnum } from "@novu/api/models/components";

    const novu = new Novu({ secretKey: "YOUR_SECRET_KEY_HERE",});

    async function run() {
      const result = await novu.subscribers.credentials.update({
        providerId: ChatOrPushProviderEnum.Fcm,
        credentials: {
          deviceTokens: [
            "token1",
            "token2",
          ],
        },
      }, "subscriberId");
    }
    run();
    ```
  </Tab>

  <Tab value="cURL">
    ```bash
    curl -L -X PUT 'https://api.novu.co/v1/subscribers/<SUBSCRIBER_ID>/credentials' \
    -H 'Content-Type: application/json' \
    -H 'Accept: application/json' \
    -H 'Authorization: ApiKey <NOVU_SECRET_KEY>' \
    -d '{
      "providerId": "fcm",
      "credentials": {
        "deviceTokens" : [
          "token1",
          "token2"
        ]
      },
      "integrationIdentifier": "string"
    }'
    ```
  </Tab>
</Tabs>

<Callout type="info">Novu automatically removes invalid device tokens from a subscribers' profile and then sends the failure details to the `MESSAGE_FAILED` webhook.</Callout>

## Step 4: Send a notification

Now you're ready to send a push notification. You can trigger a notification to a subscriber who has a registered device token.

```typescript
import { Novu } from '@novu/api';

const novu = new Novu({
  secretKey: "<NOVU_SECRET_KEY>",
});

await novu.trigger({
  workflowId: "workflowId",
  to: {
    subscriberId: 'SUBSCRIBER_ID',
  },
  payload: {
    // Your payload data
  },
});
```

## Using multiple FCM integrations

If you have multiple active FCM integrations, then you can specify which integration to associate the tokens with by providing the `integrationIdentifier`.

You can find this identifier in your Novu dashboard on the integration's settings page.

![Integration identifier](/images/channels-and-providers/push/integrationidentifier.png)

```typescript
import { Novu } from '@novu/api';

const novu = new Novu({
  secretKey: "<NOVU_SECRET_KEY>",
});

await novu.subscribers.credentials.update(
  {
    providerId: "fcm",
    // Use integrationIdentifier to store device tokens for a specific integration
    integrationIdentifier: "string",
    credentials: {
      deviceTokens: [
        "token1",
        "token2"
      ]
    },
  },
  "subscriberId"
);
```

## Using overrides to customize notifications

Novu lets you customize the behavior of push notifications by using the overrides field when triggering workflows. Overrides give you full control over message content and delivery parameters that aren’t configurable from the Novu workflow editor.

To learn more about how overrides work across all channels, see the [Trigger Overrides](/platform/integrations/trigger-overrides) documentation.

### Override FCM field

Overrides let you send platform-specific data that is not available in the workflow editor. The overrides field supports:

* `apns` overrides
* `android` overrides
* `webpush` overrides
* `fcmOptions` overrides

| Override field | Type / Interface | Link                                                                                                                                                                                         |
| -------------- | ---------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| android        | AndroidConfig    | [https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.androidconfig](https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.androidconfig) |
| apns           | ApnsConfig       | [https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.apnsconfig](https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.apnsconfig)       |
| webPush        | WebpushConfig    | [https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.webpushconfig](https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.webpushconfig) |
| fcmOptions     | FcmOptions       | [https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.fcmoptions](https://firebase.google.com/docs/reference/admin/node/firebase-admin.messaging.fcmoptions)       |

You can use these fields to customize how notifications are sent to Android, iOS via APNS, or web clients.

```typescript
await novu.trigger({
  workflowId: "workflowId",
  to: {
    subscriberId: "subscriberId",
  },
  payload: {
    key: "value",
  },
  overrides: {
    fcm: {
      // For a data-only notification (silent push)
      type: 'data',
      data: {
        custom_key: 'custom_value',
      },
      // Platform-specific overrides
      android: {
        // See FCM AndroidConfig options
      },
      apns: {
        // See FCM ApnsConfig options
      },
      webPush: {
        // See FCM WebpushConfig options
      },
      fcmOptions: {
        // See FCM FcmOptions
      }
    },
  },
});
```

### Override FCM notification content

By default, Novu sends the FCM notification content written in the step editor workflow. However, you can override the notification content by using the `overrides` field.

```typescript
import { Novu } from '@novu/api';

const novu = new Novu({
  secretKey: "<NOVU_SECRET_KEY>",
  // Required if using EU region
  // serverURL: "https://eu.api.novu.co",
});

await novu.trigger({
  workflowId: "workflowId",
  to: {
    subscriberId: "subscriberId",
  },
  payload: {
    key: "value",
  },
  overrides: {
    providers: {
      fcm: {
        type: "data",

        // URL of an image to be displayed in the notification.
        imageUrl: "https://domain.com/image.png",

        // If type is not set, you can use the "data" override to send notification messages with optional data payload
        data: {
          key: "value",
        },

        // Check FCM Overrides section above for these types
        android: {},
        apns: {},
        webPush: {},
        fcmOptions: {},
      },
    },
  },
});
```

<Callout>Overrides can be applied at runtime to customize or enrich notifications based on user context, device type, or workflow logic.</Callout>

## Sending notifications to FCM topics

<a href="https://firebase.google.com/docs/cloud-messaging/android/topic-messaging" target="_blank" rel="noopener noreferrer">FCM topics</a> are used to send notifications to multiple devices at once. In the `overrides`, you need to specify the [topic](/platform/concepts/topics) you want to send the notification to.

```typescript
import { Novu } from '@novu/api';

const novu = new Novu({
  secretKey: "<NOVU_SECRET_KEY>",
  // Required if using EU region
  // serverURL: "https://eu.api.novu.co",
});

await novu.trigger({
  workflowId: "workflowId",
  to: {
    subscriberId: "subscriberId",
  },
  payload: {
    key: "value",
  },
  overrides: {
    providers: {
      fcm: {
        topic: "topic-123",
      },
    },
  },
});
```

## Web push with relative links

Suppose you're using the Firebase (FCM) provider to send push notifications to web browsers via Novu and want users to be returned to the website after clicking the notification.

In that case, you must use the `link` property with a relative URL.

<Tabs items={['Node.js', 'Curl']}>
  <Tab value="Node.js">
    ```typescript
    import { Novu } from '@novu/api';

    const novu = new Novu({
      secretKey: "<NOVU_SECRET_KEY>",
      // Required if using EU region
      // serverURL: "https://eu.api.novu.co",
    });

    await novu.trigger({
      workflowId: "workflowId",
      to: {
        subscriberId: "subscriberId",
      },
      payload: {
        key: "value",
      },
      overrides: {
        providers: {
          fcm: {
            webPush: {
              fcmOptions: {
                link: "/foo",
              },
            },
          },
        },
      },
    });
    ```
  </Tab>

  <Tab value="Curl">
    ```bash
    curl --location --request POST 'https://url.to.our.selfhosted.novu' \
        --header 'Authorization: ApiKey KEY' \
        --header 'Content-Type: application/json' \
        --data-raw '{
            "name": "workflow-name",
            "to": {
                "subscriberId": "subscriberId"
            },
            "overrides": {
              "fcm": {
                "webPush": {
                  "fcm_options": {
                    "link": "/foo"
                  }
                }
              }
            }
          }'
    ```
  </Tab>
</Tabs>

## Frequently asked questions

<Accordions type="multiple">
  <Accordion title="FCM cost">As per Firebase <a href="https://firebase.google.com/pricing" target="_blank" rel="noopener noreferrer">pricing</a>, **Cloud Messaging** product is free to use. If other Firebase products are used, then the cost are charged per the product.</Accordion>

  <Accordion title="The registration token is not a valid FCM registration token">
    You might come across an error such as: `Sending message failed due to "The registration token is not a valid FCM registration token"`. This error happens because of an invalid or stale token. The fix for this is:

    1. Remove the old tokens.
    2. Generate a new token.
    3. Save the new token into user subscribers.
  </Accordion>

  <Accordion title="FCM notifications sent successfully with no error but push notification is not received in device">Try to generate a new token after clearing device cache and retry with this fresh token.</Accordion>
  <Accordion title="Sending message failed due to 'Requested entity was not found'">This error occurs when your token is no longer valid. To fix this, generate a new token and use it.</Accordion>
  <Accordion title="Subscriber does not have a configured channel error">This error occurs if the FCM integration is active, but the subscriber is missing from the FCM credentials (deviceTokens). The credentials (deviceTokens) for the subscriber needs to be set.</Accordion>
  <Accordion title="How to send desktop notifications using FCM">Desktop notifications for websites can be sent using FCM webpush.</Accordion>
</Accordions>