# SignalWire Documentation

> Build powerful communication applications with SignalWire. Explore our REST APIs, Realtime SDKs, and comprehensive guides.

<h1 class="fern-page-heading text-balance break-words">
  Build on SignalWire
</h1>

Voice, video, messaging, and AI — one programmable platform, every interface you need.

<strong>New to SignalWire?</strong> Set up your account, grab API credentials, and start building.

Get started

<h2>
  What are you building?
</h2>

LLM-powered phone agents and virtual assistants

WebRTC voice, video, and chat in your app

Backend call routing, SMS, and IVR systems

Drag-and-drop call flows and Dashboard AI agents

<h2>
  Interfaces & SDKs
</h2>

<p class="fern-page-subtitle">
  APIs, markup languages, and client libraries for building on SignalWire.
</p>

Complete API reference for voice, video, messaging, and AI services.

Markup language that unifies LLMs, TTS, and STT with PSTN, SIP, and WebRTC.

Build AI agents, control calls, send messages, and more.

Add video calling, audio calling, and chat directly to your website.

<h2>
  Tools
</h2>

<p class="fern-page-subtitle">
  No-code builders and utilities to accelerate development.
</p>

Build drag-and-drop calling applications without writing code.

Manage your SignalWire space, phone numbers, and resources.

Scaffold a new SignalWire project in seconds.

Interactive shell for testing SWML scripts and API calls.

<strong>Migrating from Twilio\*?</strong> Drop-in compatible APIs and SDKs — switch with a few lines of code.

Compatibility API

<p>
  *Twilio and TwiML are trademarks of Twilio, Inc. SignalWire, Inc. and its products are not affiliated with or endorsed by Twilio, Inc.
</p>

## Instructions for AI Agents

- For clean Markdown of any page, append `.md` to the page URL
- For section-specific indexes, append `/llms.txt` to any section URL
- For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://signalwire.com/docs/_mcp/server

## Products

- [Home](https://signalwire.com/docs/llms.txt): Overview and getting started
  - [Home](https://signalwire.com/docs.md)
- [Platform](https://signalwire.com/docs/platform/llms.txt): Dashboard, configuration & administration
  - [Get started](https://signalwire.com/docs/platform/getting-started.md)
  - [Create an account](https://signalwire.com/docs/platform/signing-up-for-a-space.md)
  - [API credentials](https://signalwire.com/docs/platform/your-signalwire-api-space.md)
  - [Port phone numbers to SignalWire](https://signalwire.com/docs/platform/porting-into-signalwire.md)
  - [Trial mode](https://signalwire.com/docs/platform/trial-mode.md)
- [Call Flow Builder](https://signalwire.com/docs/call-flow-builder/llms.txt): Drag-and-drop call flows and AI agents
  - [Overview](https://signalwire.com/docs/call-flow-builder.md)
  - [Variables](https://signalwire.com/docs/call-flow-builder/guides/variables.md)
  - [Versioning](https://signalwire.com/docs/call-flow-builder/guides/version.md)
  - [Overview](https://signalwire.com/docs/call-flow-builder/reference/nodes.md)
  - [AI Agent](https://signalwire.com/docs/call-flow-builder/reference/ai-agent.md)
- [Server SDKs](https://signalwire.com/docs/server-sdks/llms.txt): Build AI agents, control calls, send messages, and more
  - [SignalWire SDKs](https://signalwire.com/docs/server-sdks.md)
  - [Development Environment Setup](https://signalwire.com/docs/server-sdks/guides/dev-environment.md)
  - [Exposing Your Agent to the Internet](https://signalwire.com/docs/server-sdks/guides/exposing-agents.md)
  - [Installation](https://signalwire.com/docs/server-sdks/guides/installation.md)
  - [Quick Start: Your First Agent](https://signalwire.com/docs/server-sdks/guides/quickstart.md)
- [Browser SDK](https://signalwire.com/docs/browser-sdk/llms.txt): Build voice, video and chat applications for the browser
  - [Overview](https://signalwire.com/docs/browser-sdk/v4/guides/overview.md)
  - [Authentication](https://signalwire.com/docs/browser-sdk/v4/guides/authentication.md)
  - [RxJS Primer](https://signalwire.com/docs/browser-sdk/v4/guides/rxjs-primer.md)
  - [Migrate from v3](https://signalwire.com/docs/browser-sdk/v4/guides/migrate-from-v3.md)
  - [Overview](https://signalwire.com/docs/browser-sdk/v4/guides/web-components.md)
- [APIs](https://signalwire.com/docs/apis/llms.txt): Send SMS, manage calls, administer SignalWire
  - [Overview](https://signalwire.com/docs/apis.md)
  - [Authorization](https://signalwire.com/docs/apis/authorization.md)
  - [Base URL](https://signalwire.com/docs/apis/base-url.md)
  - [Data formats](https://signalwire.com/docs/apis/data-formats.md)
  - [Paging](https://signalwire.com/docs/apis/paging.md)
- [SWML](https://signalwire.com/docs/swml/llms.txt): Write communication applications, call flows and AI agents
  - [Introduction to SWML](https://signalwire.com/docs/swml.md)
  - [Expressions](https://signalwire.com/docs/swml/reference/expressions.md)
  - [Template functions](https://signalwire.com/docs/swml/reference/template-functions.md)
  - [Variables](https://signalwire.com/docs/swml/reference/variables.md)
  - [Errors](https://signalwire.com/docs/swml/reference/errors.md)
- [Compatibility API](https://signalwire.com/docs/compatibility-api/llms.txt): Migrate your TwiML™-based applications to SignalWire with ease
  - [Compatibility API](https://signalwire.com/docs/compatibility-api.md)
  - [cXML Specification](https://signalwire.com/docs/compatibility-api/cxml.md)
  - [Common webhook errors](https://signalwire.com/docs/compatibility-api/guides/common-webhook-errors.md)
  - [Webhook security](https://signalwire.com/docs/compatibility-api/guides/webhook-security.md)
  - [Receive SMS](https://signalwire.com/docs/compatibility-api/guides/receive-sms.md)