Auth0 simulator

Read about this simulator on our blog: Simplified Local Development and Testing with Auth0 Simulation.

Table of Contents

• Auth0 simulator
  • Table of Contents
  • Quick Start
    • Using Default User
    • Code
    • Example
  • Configuration
    • Options
    • Rules
  • Endpoints

Please read the main README for more background on simulacrum.

The auth0 simulator has been initially written to mimic the responses of a real auth0 server that is called from auth0 client libraries like auth0/react and auth0-spa-js that use the OpenID authorization code flow.

If this does not meet your needs then please create a github issue to start a conversation about adding new OpenID flows.

Quick Start

This quick start assumes you have your own app with Auth0.

[!IMPORTANT]
The Auth0 clients expect the server to be served as https, and will throw an error if it is served as http. Currently, we rely on a certificate available in the home directory. On first run, you will see instructions on how to set up this certificate through mkcert.

Using Default User

You may start a server directly from the command line.

npx @simulacrum/auth0-simulator  # this will start a simulation server at http://localhost:4400

Given no further input, it will use the default values as below. This will point your app at the simulation instead of the Auth0 endpoint.

{
  "domain": "https://localhost:4400",
  "clientId": "00000000000000000000000000000000",
  "audience": "https://thefrontside.auth0.com/api/v1/"
}

You now have a running auth0 server!

Code

You may import and run the simulation server in a script.

import { simulation } from "@simulacrum/auth0-simulator";

const app = simulation();
app.listen(4400, () =>
  console.log(`auth0 simulation server started at https://localhost:4400`)
);

By passing an initialState, you may control the initial users in the store.

Example

The folks at Auth0 maintain many samples such as github.com/auth0-samples/auth0-react-samples. Follow the instructions to run the sample, set the configuration in auth_config.json to match the defaults as noted above, and run the Auth0 simulation server with npx auth0-simulator.

Configuration

The Auth0 Simulator uses cosmiconfig to load the configuration options. This provides many options in where to place your configuration. Using the module name, auth0Simulator, you could, for example, set your configuration in a .auth0Simulatorrc.json file.

Options

The options field supports the auth0 configuration fields. The option fields should match the fields in the client application that is calling the auth0 server.

The scope also accepts an array of objects containing clientId, scope and optionally audience to enable dynamic scopes from a single simulator. This should allow multiple clients to all use the same simulator. Additionally, setting the clientId: "default" will enable a default fallback scope so every client does not need to be included.

An optional rulesDirectory field can specify a directory of auth0 rules code files, more on this below.

Rules

It is possible to run auth0 rules if the compiled code files are on disk and all located in the same directory.

Set the rulesDirectory of the options field to a path relative to your current working directory.

For example, a sample rules directory is in the auth0 package for testing.

If we want to run these rules files then we would add the rulesDirectory field to the options object.

Endpoints

The following endpoints have been assigned handlers:

• /authorize
• /login
• /u/login
• /usernamepassword/login
• /login/callback
• /oauth/token
• /v2/logout
• /.well-known/jwks.json
• /.well-known/openid-configuration