> ## Documentation Index
> Fetch the complete documentation index at: https://developers.smsmanager.com/llms.txt
> Use this file to discover all available pages before exploring further.

# SmsManager Developer Documentation

> Send SMS, Viber, and WhatsApp messages via a unified API. Explore step-by-step guides, full API reference, and ready-to-run integration examples.

Welcome to the SmsManager developer documentation. SmsManager is a multi-channel messaging API that lets you send SMS, Viber, and WhatsApp messages from a single, unified integration. Whether you're building transactional alerts, bulk campaigns, or phone number verification flows, you'll find everything you need here.

<CardGroup cols={2}>
  <Card title="Introduction" icon="book-open" href="/en/introduction">
    Learn what SmsManager is, how it works, and which API surfaces are available.
  </Card>

  <Card title="Quickstart" icon="rocket" href="/en/quickstart">
    Send your first message in minutes with a step-by-step walkthrough.
  </Card>

  <Card title="JSON API v2" icon="code" href="/en/api-reference/json-v2/overview">
    Explore the full reference for the primary message-sending API.
  </Card>

  <Card title="Webhooks" icon="webhook" href="/en/guides/webhooks">
    Receive real-time delivery notifications and inbound message events.
  </Card>
</CardGroup>

## What you can build

SmsManager gives you the building blocks for a wide range of messaging use cases:

* **Bulk SMS campaigns** — reach thousands of recipients in a single API call using the `/messages` batch endpoint
* **Transactional alerts** — deliver order confirmations, shipping updates, and account notifications reliably via SMS
* **Viber and WhatsApp messaging** — send rich messages over OTT channels using the multi-channel `flow` property
* **Phone number verification (OTP)** — integrate one-time passcodes into your sign-up or login flows with the Verify API
* **Delivery tracking** — monitor message status in real time through webhooks and delivery receipts

## API surfaces

SmsManager exposes four distinct APIs, each designed for a specific purpose.

<CardGroup cols={2}>
  <Card title="JSON API v2" href="/en/api-reference/json-v2/overview">
    The primary sending API. Post to `/message` or `/messages` to deliver SMS, Viber, and WhatsApp messages to one or more recipients.
  </Card>

  <Card title="REST API" href="/en/api-reference/rest/overview">
    Manage your account, create and configure sub-keys, and query account metadata.
  </Card>

  <Card title="Verify API" href="/en/api-reference/verify/overview">
    Generate and validate one-time passcodes for phone number verification and two-factor authentication.
  </Card>

  <Card title="WhatsApp Partner API" href="/en/api-reference/waba/overview">
    Onboard and manage WhatsApp Business Accounts (WABA) for your platform or customers.
  </Card>
</CardGroup>