API Reference

Every endpoint is authenticated with an API key sent as a Bearer token or an x-api-key header. Create a key in your dashboard, then call the JSON REST API below.

Authentication

# Pass your key as a Bearer token
curl https://your-app.com/api/v1/me \
  -H "Authorization: Bearer sk_live_..."

# ...or as an x-api-key header
curl https://your-app.com/api/v1/me \
  -H "x-api-key: sk_live_..."

Send an SMS

Send a text message to any phone number in E.164 format.

POST/api/v1/messages

Parameters

tostringrequired: Destination number, e.g. +15551234567.
fromstring: Sender number or ID.
bodystringrequired: The message text. Long messages are split into segments.

Request

curl -X POST /api/v1/messages \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+15551234567",
    "body": "Your code is 123456"
  }'

Response

{
  "id": "msg_128",
  "object": "message",
  "channel": "sms",
  "to": "+15551234567",
  "segments": 1,
  "status": "queued",
  "provider_id": "SM3f9a...",
  "created_at": "2026-07-19T12:00:00.000Z"
}

Send a WhatsApp message

Deliver a message over WhatsApp. Same shape as SMS.

POST/api/v1/whatsapp

Parameters

tostringrequired: Recipient WhatsApp number in E.164 format.
fromstring: Your WhatsApp sender number.
bodystringrequired: The message text.

Request

curl -X POST /api/v1/whatsapp \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+15551234567",
    "body": "Hi from WhatsApp!"
  }'

Response

{
  "id": "msg_129",
  "object": "message",
  "channel": "whatsapp",
  "status": "queued",
  "provider_id": "WA8c21...",
  "created_at": "2026-07-19T12:00:00.000Z"
}

Place a voice call

Start an outbound call and speak a message or run TwiML-style instructions.

POST/api/v1/calls

Parameters

tostringrequired: Number to call, E.164 format.
fromstring: Caller ID number.
messagestringrequired: Text to speak. Alternatively pass `twiml`.

Request

curl -X POST /api/v1/calls \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+15551234567",
    "message": "Hello from Relay."
  }'

Response

{
  "id": "call_54",
  "object": "call",
  "channel": "voice",
  "status": "queued",
  "provider_id": "CA1b77...",
  "created_at": "2026-07-19T12:00:00.000Z"
}

Send an email

Send a transactional email. Delivered for real over SMTP when configured.

POST/api/v1/email

Parameters

tostringrequired: Recipient email address.
fromstring: Sender address. Defaults to your configured SMTP_FROM.
subjectstringrequired: Email subject line.
textstring: Plain-text body. Provide `text` or `html`.
htmlstring: HTML body. Provide `text` or `html`.

Request

curl -X POST /api/v1/email \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "to": "user@example.com",
    "subject": "Welcome",
    "text": "Thanks for signing up!"
  }'

Response

{
  "id": "email_77",
  "object": "email",
  "channel": "email",
  "status": "sent",
  "provider_id": "<abc@smtp>",
  "created_at": "2026-07-19T12:00:00.000Z"
}

Verify a key / get account

A simple GET endpoint (no body) to confirm a key is valid and identify the owner.

GET/api/v1/me

Parameters

Request

curl /api/v1/me \
  -H "Authorization: Bearer sk_live_..."

Response

{
  "object": "account",
  "id": "user_...",
  "name": "Ada Lovelace",
  "email": "ada@example.com",
  "key_id": "key_3",
  "authenticated": true
}