API Overview - Trackly SMS

The Trackly SMS API allows you to send SMS messages programmatically. Use it to integrate SMS into your applications, automate sends from your systems, or build custom integrations.

Base URL

All API requests should be made to:

https://api.tracklysms.com/api

API Versions

The v1 API is deprecated. All v1 endpoints will continue to work but include deprecation headers in responses. Please migrate to v2 as soon as possible.

Version	Status	Notes
v1	Deprecated	Legacy API, includes deprecation headers
v2	Current	Production API with enhanced endpoints and features

Authentication

All API requests require authentication using an API key passed in the X-Api-Key header.

curl -X POST https://api.tracklysms.com/api/v2/send \
  -H "X-Api-Key: trk_your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{"to": "+14155551234", "body": "Hello!", "list_number": "+18005551234"}'

The v2 API uses to for the recipient phone number and list_number for the sending phone number (E.164 format).

See Authentication for details on obtaining and managing API keys.

V2 API (Current)

The v2 API is the current, recommended version with full support for contacts, audiences, creatives, schedules, revenue tracking, and more. View V2 API Reference

V2 API Overview

Full v2 API reference with all endpoints

Send Messages

Send single and bulk SMS messages

Contacts

Create, list, and manage contacts

Audiences

Build dynamic audience segments

Schedules

Schedule and automate campaigns

Migration Guide

Upgrade from v1 to v2

V1 API (Deprecated)

Messages (v1)

Send messages (deprecated)

Contacts (v1)

Contact stubs (no-op)

Webhooks

Delivery status webhooks

Error Codes

V1 error reference

Request Format

All requests must include Content-Type: application/json
Phone numbers should be in E.164 format (e.g., +14155551234)
Request bodies must be valid JSON

Response Format

All responses are JSON with a consistent structure:

Success — V2 (2xx)
Success — V1 (2xx)
Error (4xx/5xx)

{
  "success": true,
  "message_id": "AbC12345",
  "status": "queued"
}

{
  "id": "6789abcd",
  "message_id": "6789abcd",
  "status": "queued",
  "segments": 1,
  "gsm7": true,
  "deprecated": true
}

{
  "error": "Error description",
  "code": "error_code"
}

Deprecation Headers

All v1 API responses include these headers:

Header	Value
`X-API-Deprecated`	`v1 is deprecated`
`Deprecation`	`true`

API Limits

Trackly SMS rate-limits API requests to 60 per minute per IP address; use bulk endpoints (up to 1,000 messages per request) to scale within that limit. See API Limits & Best Practices for the full rate-limit, payload-size, and batch guidance.

SDKs & Libraries

Currently, we recommend using standard HTTP libraries in your preferred language:

curl -X POST https://api.tracklysms.com/api/v2/send \
  -H "X-Api-Key: trk_your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+14155551234",
    "body": "Hello from Trackly!",
    "list_number": "+18005551234"
  }'

import requests

response = requests.post(
    "https://api.tracklysms.com/api/v2/send",
    headers={
        "X-Api-Key": "trk_your_api_key_here",
        "Content-Type": "application/json"
    },
    json={
        "to": "+14155551234",
        "body": "Hello from Trackly!",
        "list_number": "+18005551234"
    }
)
print(response.json())

const response = await fetch("https://api.tracklysms.com/api/v2/send", {
  method: "POST",
  headers: {
    "X-Api-Key": "trk_your_api_key_here",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    to: "+14155551234",
    body: "Hello from Trackly!",
    list_number: "+18005551234",
  }),
});
console.log(await response.json());

​Base URL

​API Versions

​Authentication

​V2 API (Current)

V2 API Overview

Send Messages

Contacts

Audiences

Schedules

Migration Guide

​V1 API (Deprecated)

Messages (v1)

Contacts (v1)

Webhooks

Error Codes

​Request Format

​Response Format

​Deprecation Headers

​API Limits

​SDKs & Libraries

​Next Steps

Send First SMS

V2 API Overview

Base URL

API Versions

Authentication

V2 API (Current)

V1 API (Deprecated)

Request Format

Response Format

Deprecation Headers

API Limits

SDKs & Libraries

Next Steps