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A utility to generate signed Firebase Authentication Tokens

Firebase Token Generator - Node.js

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Firebase Custom Login gives you complete control over user authentication by allowing you to authenticate users with secure JSON Web Tokens (JWTs). The auth payload stored in those tokens is available for use in your Firebase security rules. This is a token generator library for Node.js which allows you to easily create those JWTs.


The Firebase Node.js token generator library is available via npm:

$ npm install firebase-token-generator --save

You can also download it via Bower:

$ bower install firebase-token-generator --save

A Note About Security

IMPORTANT: Because token generation requires your Firebase Secret, you should only generate tokens on trusted servers. Never embed your Firebase Secret directly into your application and never share your Firebase Secret with a connected client.

Generating Tokens

To generate tokens, you'll need your Firebase Secret which you can find by entering your Firebase URL into a browser and clicking the "Secrets" tab on the left-hand navigation menu.

Once you've downloaded the library and grabbed your Firebase Secret, you can generate a token with this snippet of Node.js code:

var FirebaseTokenGenerator = require("firebase-token-generator");
var tokenGenerator = new FirebaseTokenGenerator("<YOUR_FIREBASE_SECRET>");
var token = tokenGenerator.createToken({uid: "1", some: "arbitrary", data: "here"});

The payload passed to createToken() is made available for use within your security rules via the auth variable. This is how you pass trusted authentication details (e.g. the client's user ID) to your Firebase security rules. The payload can contain any data of your choosing, however it must contain a "uid" key, which must be a string of less than 256 characters. The generated token must be less than 1024 characters in total.

Token Options

A second options argument can be passed to createToken() to modify how Firebase treats the token. Available options are:

  • expires (Number) - A timestamp (as number of seconds since the epoch) denoting the time after which this token should no longer be valid.

  • notBefore (Number) - A timestamp (as number of seconds since the epoch) denoting the time before which this token should be rejected by the server.

  • admin (Boolean) - Set to true if you want to disable all security rules for this client. This will provide the client with read and write access to your entire Firebase.

  • debug (Boolean) - Set to true to enable debug output from your security rules. This debug output will be automatically output to the JavaScript console. You should generally not leave this set to true in production (as it slows down the rules implementation and gives your users visibility into your rules), but it can be helpful for debugging.

Here is an example of how to use the second options argument:

var FirebaseTokenGenerator = require("firebase-token-generator");
var tokenGenerator = new FirebaseTokenGenerator("<YOUR_FIREBASE_SECRET>");
var token = tokenGenerator.createToken(
  {uid: "1", some: "arbitrary", data: "here"},
  {admin: true}

Testing and Compiling From Source

Prior to compiling from source, install all necessary dependencies:

$ git clone
$ git submodule update --init
$ npm install -g grunt-cli mocha phantomjs
$ npm install
$ grunt