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npm package Node.js version

OAuth 2 mock server. Intended to be used for development or testing purposes.

When developing an application that exposes or consumes APIs that are secured with an OAuth 2 authorization scheme, a mechanism for issuing access tokens is needed. Frequently, a developer needs to create custom code that fakes the creation of tokens for testing purposes, and these tokens cannot be properly verified, since there is no actual entity issuing those tokens.

The purpose of this package is to provide an easily configurable OAuth 2 server, that can be set up and teared down at will, and can be programatically run while performing automated tests.

Warning: This tool is not intended to be used as an actual OAuth 2 server. It lacks many features that would be required in a proper implementation.

Development prerequisites

How to use


Add it to your Node.js project as a development dependency:

With yarn...

yarn add -D oauth2-mock-server

...or with npm

npm install --save-dev oauth2-mock-server


Here is an example for creating and running a server instance with a single random RSA key:

const { OAuth2Server } = require('oauth2-mock-server');

let server = new OAuth2Server();

// Generate a new RSA key and add it to the keystore
await server.issuer.keys.generateRSA();

// Start the server
await server.start(8080, 'localhost');
console.log('Issuer URL:', server.issuer.url); // -> http://localhost:8080

// Do some work with the server
// ...

// Stop the server
await server.stop();

Any number of existing JSON-formatted or PEM-encoded keys can be added to the keystore:

// Add an existing JWK key to the keystore
await server.issuer.keys.add({
  kid: 'some-key',
  kty: 'RSA',
  // ...

// Add an existing PEM-encoded key to the keystore
const fs = require('fs');

let pemKey = fs.readFileSync('some-key.pem');
await server.issuer.keys.addPEM(pemKey, 'some-key');

JSON Web Tokens (JWT) can be built programmatically:

const request = require('request');

// Build a new token
let token = server.issuer.buildToken(true);

// Call a remote API with the token
  { auth: { bearer: token } },
  function callback(err, res, body) {
    /* ... */

Customization hooks

It also provides a convenient way, through event emitters, to programmatically customize the server processing. This is particularly useful when expecting the OIDC service to behave in a specific way on one single test:

  • The JWT access token

    // Modify the expiration time on next token produced
    service.once('beforeTokenSigning', (token, _req) => {
      const timestamp = Math.floor( / 1000);
      token.payload.exp = timestamp + 400;
    // Add the client ID to a token
    const basicAuth = require('basic-auth');
    service.once('beforeTokenSigning', (token, req) => {
      const credentials = basicAuth(req);
      const clientId = credentials ? : req.body.client_id;
      token.payload.client_id = clientId;
  • The token endpoint response body and status

    // Force the oidc service to provide an invalid_grant response on next call to the token endpoint
    service.once('beforeResponse', (tokenEndpointResponse, req) => {
      tokenEndpointResponse.body = {
        error: 'invalid_grant',
      tokenEndpointResponse.statusCode = 400;
  • The userinfo endpoint response body and status

    // Force the oidc service to provide an error on next call to userinfo endpoint
    service.once('beforeUserinfo', (userInfoResponse, req) => {
      userInfoResponse.body = {
        error: 'invalid_token',
        error_message: 'token is expired',
      userInfoResponse.statusCode = 401;
  • The revoke endpoint response body and status

    // Simulates a custom token revocation body
    service.once('beforeRevoke', (revokeResponse, req) => {
      revokeResponse.body = {
        result: 'revoked',
  • The authorization endpoint redirect uri and query parameters

    // Modify the uri and query parameters before the authorization redirect
    service.once('beforeAuthorizeRedirect', (authorizeRedirectUri, req) => {
      authorizeRedirectUri.url.searchParams.set('foo', 'bar');

Supported endpoints

GET /.well-known/openid-configuration

Returns the OpenID Provider Configuration Information for the server.

GET /jwks

Returns the JSON Web Key Set (JWKS) of all the keys configured in the server.

POST /token

Issues access tokens. Currently, this endpoint is limited to:

  • No authentication
  • Client Credentials grant
  • Resource Owner Password Credentials grant
  • Authorization code grant
  • Refresh token grant

GET /authorize

It simulates the user authentication. It will automatically redirect to the callback endpoint sent as parameter. It currently supports only 'code' response_type.

GET /userinfo

It provides extra userinfo claims.

POST /revoke

It simulates a token revocation. This endpoint should always return 200 as stated by RFC 7009.

Command-Line Interface

The server can be run from the command line. You can either install it globally:

npm install -g oauth2-mock-server
oauth2-mock-server --help

or run it directly:

npx oauth2-mock-server --help


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