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Compatibility APIs | SignalWire

Same XML. Same Endpoints. A Better Provider.

This API may look familiar, and that’s by design. SignalWire’s Compatibility APIs let you preserve your existing TwiML and REST API patterns, while offering two paths to easily migrate from legacy CPaaS to a more programmable communications stack.

Don’t choose between keeping your current codebase and gaining new capabilities. Continue building while unlocking advanced capabilities like real-time transcription, AI agents, and programmable voice flows.

Compatibility XML (cXML)

A drop in replacement for TwiML that supports the same verbs and call flow logic.

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REST Compatibility API

Matches the structure and behavior of Twilio’s REST APIs. Simply update the base URL.

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Messaging XML

Define message handling instructions based on message content, sender, and date.

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Voice XML

Execute logic in real-time, enabling dynamic control based on caller ID, time of day, and call content.

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Fax XML

Trigger automated routing, storage, or custom responses with XML-based instructions for incoming faxes.

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Upgrade Without Rebuilding

SignalWire’s Compatibility APIs are engineered to mirror Twilio’s XML and REST behaviors—so you can deploy without rework. Use your same verbs, webhooks, and endpoints to go live in minutes. Then, unlock advanced features like:

Real-Time Transcription
Real-Time Transcription

Convert live audio from calls into text instantly, enabling searchable logs, live captions, or downstream analysis—all within the same call flow.

AI Voice Agents
AI Voice Agents

Deploy programmable voice agents that can speak naturally, respond to caller intent, and trigger actions—without writing your own NLP stack.

Programmable SIP  & Trunking
Programmable SIP & Trunking

Tie your app into existing SIP infrastructure or PBXs, or create remote endpoints using SIP registration.

Git the Code

SignalWire Compatibility XML (cXML) code snippets

Answering Calls with TTS

Answer incoming calls, respond with Text-To-Speech then connect to another number using simple XML instructions.

Git Code
Forward a Call

Forward incoming calls using SignalWire cXML and the <Dial> verb. Route a call to any external number while preserving the original caller ID.

Git Code
Interactive Voice Response (IVR)

Use <Say> and <Gather> to guide callers and collect input via keypress.

Git Code
Send SMS with Follow-up Logic

Send SMS messages and define a follow-up action using the action attribute. After delivering the message, SignalWire makes a request to a specified URL, allowing the application to continue the conversation, log activity, or trigger additional workflows.

Git Code
Redirect to Absolute URL

The <Redirect> verb transfers control from the current document to another. It is effectively an exit statement from the current document.

Git Code
Store Fax Image

Media from the incoming fax will be stored on SignalWire's server in TIFF format.

Git Code

We speak your language.

Our Compatibility SDKs support Node.js, Python, Ruby, C#, and more, making it easy to plug your code into SignalWire with just a package install.

Resources

Build on a Platform that
Gets Your Codebase.

Contact us to get started.

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