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Emulate apple

Emulated Sign in with Apple / Apple OIDC for local development and testing. Use when the user needs to test Apple sign-in locally, emulate Apple OIDC discovery, handle Apple token exchange, configure Apple OAuth clients, or work with Apple userinfo without hitting real Apple APIs. Triggers include "Apple OAuth", "emulate Apple", "mock Apple login", "test Apple sign-in", "Sign in with Apple", "Apple OIDC", "local Apple auth", or any task requiring a local Apple OAuth/OIDC provider.

install
source · Clone the upstream repo
git clone https://github.com/vercel-labs/emulate
Claude Code · Install into ~/.claude/skills/
T=$(mktemp -d) && git clone --depth=1 https://github.com/vercel-labs/emulate "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/apple" ~/.claude/skills/vercel-labs-emulate-apple && rm -rf "$T"
manifest: skills/apple/SKILL.md
source content

Apple Sign In Emulator

Sign in with Apple emulation with authorization code flow, PKCE support, RS256 ID tokens, and OIDC discovery.

Start

# Apple only
npx emulate --service apple

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

Or programmatically:

import { createEmulator } from 'emulate'

const apple = await createEmulator({ service: 'apple', port: 4004 })
// apple.url === 'http://localhost:4004'

Pointing Your App at the Emulator

Environment Variable

APPLE_EMULATOR_URL=http://localhost:4004

OAuth URL Mapping

Real Apple URLEmulator URL
https://appleid.apple.com/.well-known/openid-configuration
$APPLE_EMULATOR_URL/.well-known/openid-configuration
https://appleid.apple.com/auth/authorize
$APPLE_EMULATOR_URL/auth/authorize
https://appleid.apple.com/auth/token
$APPLE_EMULATOR_URL/auth/token
https://appleid.apple.com/auth/keys
$APPLE_EMULATOR_URL/auth/keys
https://appleid.apple.com/auth/revoke
$APPLE_EMULATOR_URL/auth/revoke

Auth.js / NextAuth.js

import Apple from '@auth/core/providers/apple'

Apple({
  clientId: process.env.APPLE_CLIENT_ID,
  clientSecret: process.env.APPLE_CLIENT_SECRET,
  authorization: {
    url: `${process.env.APPLE_EMULATOR_URL}/auth/authorize`,
    params: { scope: 'openid email name', response_mode: 'form_post' },
  },
  token: {
    url: `${process.env.APPLE_EMULATOR_URL}/auth/token`,
  },
  jwks_endpoint: `${process.env.APPLE_EMULATOR_URL}/auth/keys`,
})

Passport.js

import { Strategy as AppleStrategy } from 'passport-apple'

const APPLE_URL = process.env.APPLE_EMULATOR_URL ?? 'https://appleid.apple.com'

new AppleStrategy({
  clientID: process.env.APPLE_CLIENT_ID,
  teamID: process.env.APPLE_TEAM_ID,
  keyID: process.env.APPLE_KEY_ID,
  callbackURL: 'http://localhost:3000/api/auth/callback/apple',
  authorizationURL: `${APPLE_URL}/auth/authorize`,
  tokenURL: `${APPLE_URL}/auth/token`,
}, verifyCallback)

Seed Config

apple:
  users:
    - email: testuser@icloud.com
      name: Test User
      given_name: Test
      family_name: User
    - email: private@example.com
      name: Private User
      is_private_email: true
  oauth_clients:
    - client_id: com.example.app
      team_id: TEAM001
      name: My Apple App
      redirect_uris:
        - http://localhost:3000/api/auth/callback/apple

When no OAuth clients are configured, the emulator accepts any 

client_id
. With clients configured, strict validation is enforced for 
client_id
and 
redirect_uri
.

Users with 

is_private_email: true
get a generated 
@privaterelay.appleid.com
email in the 
id_token
instead of their real email.

API Endpoints

OIDC Discovery

curl http://localhost:4004/.well-known/openid-configuration

Returns the standard OIDC discovery document with all endpoints pointing to the emulator:

{
  "issuer": "http://localhost:4004",
  "authorization_endpoint": "http://localhost:4004/auth/authorize",
  "token_endpoint": "http://localhost:4004/auth/token",
  "jwks_uri": "http://localhost:4004/auth/keys",
  "revocation_endpoint": "http://localhost:4004/auth/revoke",
  "response_types_supported": ["code"],
  "subject_types_supported": ["pairwise"],
  "id_token_signing_alg_values_supported": ["RS256"],
  "scopes_supported": ["openid", "email", "name"],
  "token_endpoint_auth_methods_supported": ["client_secret_post"],
  "response_modes_supported": ["query", "fragment", "form_post"]
}

JWKS

curl http://localhost:4004/auth/keys

Returns an RSA public key (

kid
: 
emulate-apple-1
) for verifying 
id_token
signatures.

Authorization

# Browser flow: redirects to a user picker page
curl -v "http://localhost:4004/auth/authorize?\
client_id=com.example.app&\
redirect_uri=http://localhost:3000/api/auth/callback/apple&\
scope=openid+email+name&\
response_type=code&\
state=random-state&\
nonce=random-nonce&\
response_mode=form_post"

Query parameters:

ParamDescription
client_id
OAuth client ID (Apple Services ID)
redirect_uri
Callback URL
scope
Space-separated scopes (
openid email name
)
state
Opaque state for CSRF protection
nonce
Nonce for ID token (optional)
response_mode
query
(default), 
form_post
, or 
fragment

The emulator renders an HTML page where you select a seeded user. After selection, it redirects (or auto-submits a form for 

form_post
) to 
redirect_uri
with 
code
and 
state
. On the first authorization per user/client pair, a 
user
JSON blob is also included (matching Apple's real behavior).

Token Exchange

curl -X POST http://localhost:4004/auth/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "code=<authorization_code>&\
client_id=com.example.app&\
client_secret=<client_secret>&\
grant_type=authorization_code"

Returns:

{
  "access_token": "apple_...",
  "refresh_token": "r_apple_...",
  "id_token": "<jwt>",
  "token_type": "Bearer",
  "expires_in": 3600
}

The 

id_token
is an RS256 JWT containing 
sub
, 
email
, 
email_verified
(string), 
is_private_email
(string), 
real_user_status
, 
auth_time
, and optional 
nonce
.

Refresh Token

curl -X POST http://localhost:4004/auth/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "refresh_token=r_apple_...&\
client_id=com.example.app&\
grant_type=refresh_token"

Returns a new 

access_token
and 
id_token
. No new 
refresh_token
is issued on refresh (matching Apple's behavior).

Token Revocation

curl -X POST http://localhost:4004/auth/revoke \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "token=apple_..."

Returns 

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

Common Patterns

Full Authorization Code Flow

APPLE_URL="http://localhost:4004"
CLIENT_ID="com.example.app"
REDIRECT_URI="http://localhost:3000/api/auth/callback/apple"

# 1. Open in browser (user picks a seeded account)
#    $APPLE_URL/auth/authorize?client_id=$CLIENT_ID&redirect_uri=$REDIRECT_URI&scope=openid+email+name&response_type=code&state=abc&response_mode=form_post

# 2. After user selection, emulator posts to:
#    $REDIRECT_URI with code=<code>&state=abc (and user JSON on first auth)

# 3. Exchange code for tokens
curl -X POST $APPLE_URL/auth/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "code=<code>&client_id=$CLIENT_ID&grant_type=authorization_code"

# 4. Decode the id_token JWT to get user info

Private Relay Email

When a user has 

is_private_email: true
in the seed config, the 
id_token
will contain a generated 
@privaterelay.appleid.com
email instead of the user's real email. This matches Apple's Hide My Email behavior.