Upstream Firebase User Auth Policy

This policy adds a Firebase Admin token to the outgoing Authentication header allowing requests to Firebase using Service Account admin permissions. This can be useful for calling Firebase services such as Firestore through a Zuplo endpoint that is secured with other means of Authentication such as API keys. Additionally, this policy can be useful for service content to all API users (for example serving a specific Firestore document containing configuration data)

We recommend reading the serviceAccountJson from environment variables (so it is not checked in to source control) using the $env(ENV_VAR) syntax.


The configuration shows how to configure the policy in the 'policies.json' document.

{ "name": "my-upstream-firebase-user-auth-inbound-policy", "policyType": "upstream-firebase-user-auth-inbound", "handler": { "export": "UpstreamFirebaseUserAuthInboundPolicy", "module": "$import(@zuplo/runtime)", "options": { "developerClaims": { "premium": true }, "expirationOffsetSeconds": 300, "serviceAccountJson": "$env(SERVICE_ACCOUNT_JSON)", "tokenRetries": 3, "userId": "1234", "webApiKey": "$env(WEB_API_KEY)" } } }

Policy Configuration

  • name <string> - The name of your policy instance. This is used as a reference in your routes.
  • policyType <string> - The identifier of the policy. This is used by the Zuplo UI. Value should be upstream-firebase-user-auth-inbound.
  • handler.export <string> - The name of the exported type. Value should be UpstreamFirebaseUserAuthInboundPolicy.
  • handler.module <string> - The module containing the policy. Value should be $import(@zuplo/runtime).
  • handler.options <object> - The options for this policy. See Policy Options below.

Policy Options

The options for this policy are specified below. All properties are optional unless specifically marked as required.

  • serviceAccountJson <string> (Required) -
    The Google Service Account key in JSON format. Note you can load this from environment variables using the $env(ENV_VAR) syntax.
  • userId <string> -
    The userId to use as the custom token's subject.
  • userIdPropertyPath <string> -
    The property on the incoming request.user object to retrieve the value of the userId.
  • developerClaims <object> -
    Additional claims to include in the custom token's payload.
  • webApiKey <string> (Required) -
    The Firebase Web API Key (found in project settings)
  • tokenRetries <number> -
    The number of times to retry fetching the token in the event of a failure.
    Defaults to 3.
  • expirationOffsetSeconds <number> -
    The number of seconds less than the token expiration to cache the token.
    Defaults to 300.

Using the Policy

Read more about how policies work

Upstream Firebase Admin Auth