@emulators/twilio

Twilio API emulator for local development and CI. Part of emulate.

npm install @emulators/twilio

Run it through the CLI:

npx emulate --service twilio

The first supported surface includes seeded Account SID/Auth Token credentials, API key credentials, incoming phone numbers, Programmable Messaging, Messaging Services, Verify, basic Voice calls, Conversations REST resources, signed webhooks, simulator routes, and an inspector.

Default local credentials:

TWILIO_ACCOUNT_SID=AC00000000000000000000000000000000
TWILIO_AUTH_TOKEN=twilio_test_auth_token
TWILIO_API_KEY=SK00000000000000000000000000000000
TWILIO_API_SECRET=twilio_test_api_secret
TWILIO_PHONE_NUMBER=+15551234567
TWILIO_VERIFY_SERVICE_SID=VA00000000000000000000000000000000

Twilio uses multiple product hosts. When testing with the official Node SDK, use a custom request client that rewrites Twilio hosts to the local emulator. The emulator exposes product-prefixed local routes such as /verify/v2 and /messaging/v1.

For SMS and OTP tests, the seeded Verify Service uses code 123456. Test runners can also read the latest local code with GET /_twilio/simulate/verification-code?To=...&ServiceSid=... using Basic auth. Inbound SMS webhooks are simulated with POST /_twilio/simulate/inbound-message, using an assigned Messaging Service inbound_request_url before falling back to the phone number sms_url. Outbound delivery transitions are simulated with POST /_twilio/simulate/message-status.

No real SMS, voice, carrier, compliance, billing, or SendGrid traffic is performed.