Alert21 — EVERY ALERT. ONE API.
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Developer Documentation

Build Your First Alert in Minutes

Alert21 is designed so developers integrate with a stable platform API while routing, telecom-provider details and compliance mappings remain behind the platform boundary.

Open Quickstart Contact Sales
JSON
{
  "to": "919876543210",
  "template_id": "1107161234567890123",
  "variables": ["Amit", "2500", "TXN88991"]
}

Developer Resources

  • Quickstart.
  • SMS API reference.
  • Authentication.
  • Webhooks.
  • Delivery statuses.
  • Error codes.
  • SDK guidance.
  • Postman collection.

API Design Principles

  • HTTPS only.
  • Versioned REST endpoints.
  • JSON requests and responses.
  • Server-side API authentication.
  • Idempotency for safe retries.
  • Consistent error envelopes.
  • Stable Alert21 Message IDs.
  • Signed webhooks.
  • Documented limits.

Start with SMS

The first production integration uses to, template_id and variables. Alert21 maps the request to the correct account-level template, sender and route configuration.

Open Quickstart
EVERY ALERT. ONE API.

Turn your next business event into a traceable alert.

Start with DLT-ready SMS today on Alert21’s developer-first communication platform.

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