Microsoft Entra ID Emulator

Microsoft Entra ID (Azure AD) v2.0 OAuth 2.0 and OpenID Connect emulation with authorization code flow, PKCE, client credentials, RS256 ID tokens, OIDC discovery, and a Microsoft Graph /v1.0/me endpoint.

Start

Local listeners bind to 127.0.0.1 by default. For access from containers or other machines, pass --host 0.0.0.0 to the CLI or hostname: '0.0.0.0' to createEmulator. Configure --base-url or baseUrl for advertised URLs reachable by those clients.

# Microsoft only
npx emulate --service microsoft

# Default port (when run alone)
# http://localhost:4000

Or programmatically:

import { createEmulator } from 'emulate'

const microsoft = await createEmulator({ service: 'microsoft', port: 4005 })
// microsoft.url === 'http://localhost:4005'

Pointing Your App at the Emulator

Environment Variable

MICROSOFT_EMULATOR_URL=http://localhost:4005

OAuth URL Mapping

Real Microsoft URL	Emulator URL
https://login.microsoftonline.com/{tenant}/v2.0/.well-known/openid-configuration	$MICROSOFT_EMULATOR_URL/{tenant}/v2.0/.well-known/openid-configuration
https://login.microsoftonline.com/.well-known/openid-configuration	$MICROSOFT_EMULATOR_URL/.well-known/openid-configuration
https://login.microsoftonline.com/common/oauth2/v2.0/authorize	$MICROSOFT_EMULATOR_URL/oauth2/v2.0/authorize
https://login.microsoftonline.com/common/oauth2/v2.0/token	$MICROSOFT_EMULATOR_URL/oauth2/v2.0/token
https://login.microsoftonline.com/common/discovery/v2.0/keys	$MICROSOFT_EMULATOR_URL/discovery/v2.0/keys
https://graph.microsoft.com/oidc/userinfo	$MICROSOFT_EMULATOR_URL/oidc/userinfo
https://graph.microsoft.com/v1.0/me	$MICROSOFT_EMULATOR_URL/v1.0/me

Auth.js / NextAuth.js

import MicrosoftEntraId from '@auth/core/providers/microsoft-entra-id'

MicrosoftEntraId({
  clientId: process.env.MICROSOFT_CLIENT_ID,
  clientSecret: process.env.MICROSOFT_CLIENT_SECRET,
  authorization: {
    url: `${process.env.MICROSOFT_EMULATOR_URL}/oauth2/v2.0/authorize`,
    params: { scope: 'openid email profile User.Read' },
  },
  token: {
    url: `${process.env.MICROSOFT_EMULATOR_URL}/oauth2/v2.0/token`,
  },
  userinfo: {
    url: `${process.env.MICROSOFT_EMULATOR_URL}/oidc/userinfo`,
  },
  issuer: process.env.MICROSOFT_EMULATOR_URL,
})

Passport.js

import { OIDCStrategy } from 'passport-azure-ad'

const MICROSOFT_URL = process.env.MICROSOFT_EMULATOR_URL ?? 'https://login.microsoftonline.com'

new OIDCStrategy({
  identityMetadata: `${MICROSOFT_URL}/.well-known/openid-configuration`,
  clientID: process.env.MICROSOFT_CLIENT_ID,
  clientSecret: process.env.MICROSOFT_CLIENT_SECRET,
  redirectUrl: 'http://localhost:3000/api/auth/callback/microsoft-entra-id',
  responseType: 'code',
  responseMode: 'query',
  scope: ['openid', 'email', 'profile'],
}, verifyCallback)

MSAL.js

import { ConfidentialClientApplication } from '@azure/msal-node'

const msalConfig = {
  auth: {
    clientId: process.env.MICROSOFT_CLIENT_ID,
    clientSecret: process.env.MICROSOFT_CLIENT_SECRET,
    authority: process.env.MICROSOFT_EMULATOR_URL,
    knownAuthorities: [process.env.MICROSOFT_EMULATOR_URL],
  },
}

const cca = new ConfidentialClientApplication(msalConfig)

Seed Config

microsoft:
  users:
    - email: testuser@outlook.com
      name: Test User
      given_name: Test
      family_name: User
      tenant_id: 9188040d-6c67-4c5b-b112-36a304b66dad
  oauth_clients:
    - client_id: example-client-id
      client_secret: example-client-secret
      name: My Microsoft App
      redirect_uris:
        - http://localhost:3000/api/auth/callback/microsoft-entra-id
      tenant_id: 9188040d-6c67-4c5b-b112-36a304b66dad

When no OAuth clients are configured, the emulator accepts any client_id. With clients configured, strict validation is enforced for client_id, client_secret, and redirect_uri.

API Endpoints

OIDC Discovery

# Default tenant
curl http://localhost:4005/.well-known/openid-configuration

# Tenant-scoped (common, organizations, consumers, or specific tenant ID)
curl http://localhost:4005/common/v2.0/.well-known/openid-configuration

Returns the standard OIDC discovery document:

{
  "issuer": "http://localhost:4005/{tenant}/v2.0",
  "authorization_endpoint": "http://localhost:4005/oauth2/v2.0/authorize",
  "token_endpoint": "http://localhost:4005/oauth2/v2.0/token",
  "userinfo_endpoint": "http://localhost:4005/oidc/userinfo",
  "end_session_endpoint": "http://localhost:4005/oauth2/v2.0/logout",
  "jwks_uri": "http://localhost:4005/discovery/v2.0/keys",
  "response_types_supported": ["code"],
  "subject_types_supported": ["pairwise"],
  "id_token_signing_alg_values_supported": ["RS256"],
  "scopes_supported": ["openid", "email", "profile", "User.Read", "offline_access"],
  "token_endpoint_auth_methods_supported": ["client_secret_post", "client_secret_basic"]
}

JWKS

curl http://localhost:4005/discovery/v2.0/keys

Returns an RSA public key (kid: emulate-microsoft-1) for verifying id_token signatures.

Authorization

# Browser flow: redirects to a user picker page
curl -v "http://localhost:4005/oauth2/v2.0/authorize?\
client_id=example-client-id&\
redirect_uri=http://localhost:3000/api/auth/callback/microsoft-entra-id&\
scope=openid+email+profile&\
response_type=code&\
state=random-state&\
nonce=random-nonce"

Query parameters:

Param	Description
client_id	OAuth client ID
redirect_uri	Callback URL
scope	Space-separated scopes (openid email profile User.Read)
state	Opaque state for CSRF protection
nonce	Nonce for ID token (optional)
response_mode	query (default) or form_post
code_challenge	PKCE challenge (optional)
code_challenge_method	plain or S256 (optional)

Token Exchange

curl -X POST http://localhost:4005/oauth2/v2.0/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "code=<authorization_code>&\
client_id=example-client-id&\
client_secret=example-client-secret&\
redirect_uri=http://localhost:3000/api/auth/callback/microsoft-entra-id&\
grant_type=authorization_code"

Returns:

{
  "access_token": "microsoft_...",
  "refresh_token": "r_microsoft_...",
  "id_token": "<jwt>",
  "token_type": "Bearer",
  "expires_in": 3600,
  "scope": "openid email profile"
}

The id_token is an RS256 JWT containing sub, oid, tid (tenant ID), email, name, preferred_username, ver ("2.0"), and optional nonce.

For PKCE, include code_verifier in the token request.

Supports Authorization: Basic header with base64-encoded client_id:client_secret as an alternative to body parameters.

Client Credentials

curl -X POST http://localhost:4005/oauth2/v2.0/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "client_id=example-client-id&\
client_secret=example-client-secret&\
grant_type=client_credentials&\
scope=https://graph.microsoft.com/.default"

Returns an access_token only (no refresh_token or id_token).

Refresh Token

curl -X POST http://localhost:4005/oauth2/v2.0/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "refresh_token=r_microsoft_...&\
client_id=example-client-id&\
client_secret=example-client-secret&\
grant_type=refresh_token"

Returns a new access_token, rotated refresh_token, and new id_token. The presenting client_id and client_secret must belong to the client that received the refresh token. Legacy refresh records without a stored client binding remain supported.

User Info

curl http://localhost:4005/oidc/userinfo \
  -H "Authorization: Bearer microsoft_..."

Returns:

{
  "sub": "<oid>",
  "email": "testuser@outlook.com",
  "name": "Test User",
  "given_name": "Test",
  "family_name": "User",
  "preferred_username": "testuser@outlook.com"
}

Microsoft Graph /me

curl http://localhost:4005/v1.0/me \
  -H "Authorization: Bearer microsoft_..."

Returns an OData-style response:

{
  "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#users/$entity",
  "displayName": "Test User",
  "mail": "testuser@outlook.com",
  "userPrincipalName": "testuser@outlook.com",
  "id": "<oid>"
}

Logout

curl "http://localhost:4005/oauth2/v2.0/logout?post_logout_redirect_uri=http://localhost:3000"

Redirects to the post_logout_redirect_uri if provided and valid.

Token Revocation

curl -X POST http://localhost:4005/oauth2/v2.0/revoke \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "token=microsoft_..."

Returns 200 OK. The token is removed from the emulator's token map.

Common Patterns

Full Authorization Code Flow

MICROSOFT_URL="http://localhost:4005"
CLIENT_ID="example-client-id"
CLIENT_SECRET="example-client-secret"
REDIRECT_URI="http://localhost:3000/api/auth/callback/microsoft-entra-id"

# 1. Open in browser (user picks a seeded account)
#    $MICROSOFT_URL/oauth2/v2.0/authorize?client_id=$CLIENT_ID&redirect_uri=$REDIRECT_URI&scope=openid+email+profile&response_type=code&state=abc

# 2. After user selection, emulator redirects to:
#    $REDIRECT_URI?code=<code>&state=abc

# 3. Exchange code for tokens
curl -X POST $MICROSOFT_URL/oauth2/v2.0/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "code=<code>&client_id=$CLIENT_ID&client_secret=$CLIENT_SECRET&redirect_uri=$REDIRECT_URI&grant_type=authorization_code"

# 4. Fetch user info with the access_token
curl $MICROSOFT_URL/oidc/userinfo \
  -H "Authorization: Bearer <access_token>"

PKCE Flow

CODE_VERIFIER=$(openssl rand -base64 32 | tr -d '=+/' | cut -c1-43)
CODE_CHALLENGE=$(echo -n $CODE_VERIFIER | openssl dgst -sha256 -binary | base64 | tr -d '=' | tr '+/' '-_')

# 1. Authorize with challenge
# $MICROSOFT_URL/oauth2/v2.0/authorize?...&code_challenge=$CODE_CHALLENGE&code_challenge_method=S256

# 2. Token exchange with verifier
curl -X POST $MICROSOFT_URL/oauth2/v2.0/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "code=<code>&client_id=$CLIENT_ID&client_secret=$CLIENT_SECRET&redirect_uri=$REDIRECT_URI&grant_type=authorization_code&code_verifier=$CODE_VERIFIER"

OIDC Discovery-Based Setup

Libraries that support OIDC discovery can auto-configure from the discovery document:

import { Issuer } from 'openid-client'

const microsoftIssuer = await Issuer.discover(
  process.env.MICROSOFT_EMULATOR_URL ?? 'https://login.microsoftonline.com/common/v2.0'
)

const client = new microsoftIssuer.Client({
  client_id: process.env.MICROSOFT_CLIENT_ID,
  client_secret: process.env.MICROSOFT_CLIENT_SECRET,
  redirect_uris: ['http://localhost:3000/api/auth/callback/microsoft-entra-id'],
})

Custom emulators alongside built-ins

Use npx emulate init --custom inventory to scaffold a third-party API emulator and test. Register it in emulate.config.ts with defineConfig from emulate, alongside built-in entries such as { emulator: "microsoft" }. Run npx emulate start --watch to reload imports and inspect custom state at the printed /_emulate URL. Successful reloads reset the run to seed. Existing flat seed configs still work; --config selects an explicit file. For authoring and testing third-party API emulators, see https://emulate.dev/docs/custom-emulators.