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

# SMS, MMS, and RCS overview

> Send text messages with OneSignal. Covers SMS, MMS, and RCS formats, the three texting program types (promotional, transactional, OTP), and setup paths for each use case.

Text reaches subscribers on the phone number they use everywhere, making it one of the most direct channels available. OneSignal supports three message formats:

* **SMS:** text-only messages up to 160 characters. Supports plain text, numbers, and emojis.
* **MMS:** extends SMS with rich media: images, video, audio, and GIFs. Supports up to 1,600 characters of text alongside the attachment.
* **RCS** (Rich Communication Services): branded, app-like experiences with buttons, carousels, keyword replies, and read receipts. Requires a dedicated RCS sender resource.

***

## Types of texting programs

OneSignal supports three types of texting programs. Each has different consent requirements, sender configurations, and compliance rules.

<Columns cols={3}>
  <Card title="Promotional messaging" icon="tag" href="./sms-promotional-messaging">
    Sales, flash offers, abandoned carts, product launches, and re-engagement campaigns.
  </Card>

  <Card title="Transactional messaging" icon="bell" href="./sms-transactional-messaging">
    Order confirmations, shipping updates, appointment reminders, and account alerts.
  </Card>

  <Card title="One-time passwords" icon="lock" href="./sms-verify">
    Verification codes, two-factor authentication, and account security messages.
  </Card>
</Columns>

<Warning>
  Each program type requires a **dedicated sender**. If a subscriber texts STOP to a shared sender, they are opted out of all messages from that sender, including transactional messages and OTPs they still want. Use separate senders per program.
</Warning>

***

## Set up SMS

Before sending, you need a brand, a sender, and at least one approved sender resource.

<Columns cols={2}>
  <Card title="SMS setup" icon="gear" href="./sms-setup">
    Understand brands, senders, and sender resources. Choose between OneSignal SMS and Twilio integration.
  </Card>

  <Card title="Sender resource applications" icon="file-check" href="./sms-registration-requirements">
    Apply for sender resources by country and type. Includes per-country approval timelines and requirements.
  </Card>

  <Card title="Opt-in and collection" icon="user-plus" href="./sms-opt-in-and-collection">
    Collect valid consent for promotional, transactional, and OTP programs.
  </Card>

  <Card title="Consent keyword management" icon="shield" href="./sms-consent-keyword-management">
    Manage STOP, HELP, START, and custom opt-out keywords.
  </Card>
</Columns>

***

## Send messages

<Columns cols={2}>
  <Card title="Composing messages" icon="pencil" href="./sms-composing-messages">
    SMS/MMS and RCS editors, character limits, segments, trackable links, and billing categories.
  </Card>

  <Card title="SMS keywords" icon="message" href="./keywords">
    Two-way keyword campaigns, preference centers, and auto-responders.
  </Card>

  <Card title="Journeys" icon="map" href="./journeys-overview">
    Automate multi-step messaging flows triggered by user actions.
  </Card>

  <Card title="API" icon="code" href="/reference/create-message">
    Send messages programmatically via the REST API.
  </Card>
</Columns>

***

## Analytics and compliance

<Columns cols={2}>
  <Card title="SMS message reports" icon="chart-bar" href="./sms-message-reports">
    Delivery metrics, click-through rates, and failure troubleshooting.
  </Card>

  <Card title="Regulatory compliance" icon="scale" href="./sms-regulatory-compliance">
    Consent standards, quiet hours, prohibited content, and fraud prevention.
  </Card>
</Columns>

***

## Supported countries

OneSignal supports sending text messages to the following countries:

| Americas      | Europe         | Asia                 | Oceania     |
| ------------- | -------------- | -------------------- | ----------- |
| Argentina     | Austria        | Hong Kong            | Australia   |
| Brazil        | Belgium        | India                | New Zealand |
| Canada        | Denmark        | Japan                |             |
| Chile         | Finland        | Macao                |             |
| Mexico        | France         | Malaysia             |             |
| Peru          | Germany        | Philippines          |             |
| Puerto Rico   | Iceland        | Singapore            |             |
| United States | Ireland        | South Korea          |             |
|               | Italy          | Taiwan               |             |
|               | Luxembourg     | Thailand             |             |
|               | Netherlands    | Turkey               |             |
|               | Norway         | United Arab Emirates |             |
|               | Poland         |                      |             |
|               | Portugal       |                      |             |
|               | Spain          |                      |             |
|               | Sweden         |                      |             |
|               | Switzerland    |                      |             |
|               | United Kingdom |                      |             |

For country-specific sender resource types, approval timelines, and compliance requirements, see [Sender resource applications](./sms-registration-requirements).