twilio

Original：🇺🇸 English

Translated

Emulated Twilio REST APIs for local development and testing. Use when the user needs to test Twilio Messaging, Verify, Voice, phone numbers, webhooks, status callbacks, inbound SMS simulation, or Twilio SDK integrations without hitting the real Twilio service.

2installs

Sourcevercel-labs/emulate

Added on2026-08-22

NPX Install

npx skill4agent add vercel-labs/emulate twilio

SKILL.md Content

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Twilio API Emulator

Stateful Twilio REST emulation with seeded accounts, Auth Tokens, API keys, incoming phone numbers, Programmable Messaging, Messaging Services, Verify, basic Voice calls, Conversations REST resources, signed webhooks, local simulator routes, and an inspector.

Start

bash

npx emulate --service twilio

Default URL:

http://localhost:4013

when all services are started, or

http://localhost:4000

when Twilio is the only service.

Defaults

text

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

URL Mapping

Real Twilio URL Emulator URL

Real Twilio URL	Emulator URL
`https://api.twilio.com/2010-04-01/...`	`$TWILIO_EMULATOR_URL/2010-04-01/...`
`https://messaging.twilio.com/v1/...`	`$TWILIO_EMULATOR_URL/messaging/v1/...`
`https://verify.twilio.com/v2/...`	`$TWILIO_EMULATOR_URL/verify/v2/...`

https://api.twilio.com/2010-04-01/...

$TWILIO_EMULATOR_URL/2010-04-01/...

https://messaging.twilio.com/v1/...

$TWILIO_EMULATOR_URL/messaging/v1/...

https://verify.twilio.com/v2/...

$TWILIO_EMULATOR_URL/verify/v2/...

The official Node SDK builds absolute Twilio product URLs. In SDK tests, use a custom request client that rewrites those hosts to the emulator prefixes above.

Auth

HTTP Basic auth accepts either:

Account SID and Auth Token
API Key SID and API Key Secret

Core Routes

POST /2010-04-01/Accounts/{AccountSid}/Messages.json

- create outbound message

GET /2010-04-01/Accounts/{AccountSid}/Messages.json

- list messages

POST /2010-04-01/Accounts/{AccountSid}/Calls.json

- create outbound call

POST /verify/v2/Services/{ServiceSid}/Verifications

- start verification

POST /verify/v2/Services/{ServiceSid}/VerificationCheck

- check verification code

POST /conversations/v1/Services/{ServiceSid}/Conversations

- create Conversation

POST /conversations/v1/Services/{ServiceSid}/Conversations/{ConversationSid}/Participants

- add participant

POST /conversations/v1/Services/{ServiceSid}/Conversations/{ConversationSid}/Messages

- add message

```
POST /_twilio/simulate/inbound-message
```
- simulate inbound SMS
```
POST /_twilio/simulate/message-status
```
- simulate message status callback
```
POST /_twilio/simulate/inbound-call
```
- simulate inbound call

SMS And OTP Testing

The seeded Verify Service code is
```
123456
```
.
Use
```
CustomCode
```
when creating a Verification to force a per-verification code.
Use
```
GET /_twilio/simulate/verification-code?To=...&ServiceSid=...
```
with Basic auth to fetch the latest local code for an E2E test.

Use

POST /_twilio/simulate/verification-status

with

VerificationSid

or

To

to force local Verify state.

Use
```
POST /_twilio/simulate/inbound-message
```
to test inbound SMS webhooks.
Inbound SMS uses an assigned Messaging Service
```
inbound_request_url
```
before falling back to the phone number
```
sms_url
```
.
Use
```
POST /_twilio/simulate/message-status
```
to test outbound status callbacks.

Current Limits

No real SMS, MMS, WhatsApp, email, voice, carrier, compliance, billing, SendGrid, Studio, Flex, TaskRouter, Video, Sync, Segment, Conversations SDK websocket behavior, or complete TwiML interpreter behavior is implemented.