Overview | SignalWire

SignalWire’s REST API allows you to manage and modify calls and messages made to or from your SignalWire phone numbers. You also have the ability to retrieve and update your account information, retrieve your entire history of calls, messages, transcriptions, media and more.

This can all be achieved by sending HTTP requests to the SignalWire REST API.

The API formerly known as LaML

The Compatibility API and cXML were previously known as “LaML”. laml still appears in endpoint URLs, and the cXML namespace of the REST Client is still titled LaML. Don’t worry, it’s all cXML!

Try it in Postman

For developers who prefer working in Postman, we maintain an official Compatibility API collection with pre-built requests for every cXML endpoint, example payloads, and a configurable environment for your SignalWire credentials. It’s a fully supported alternative to the API playground built into these docs — useful if Postman is already part of your workflow.

Open the collection in Postman

Click Run in Postman to fork the collection into your own Postman workspace.

Set your environment variables

Open the collection’s Variables tab and fill in your Space subdomain, AccountSid (your Project ID — see AccountSid vs ProjectID below), and Auth Token from the API pane of your SignalWire Dashboard.

Send your first request

Open any endpoint — try Calls to list the calls on your project, or Messages to send a test SMS — and hit Send. The collection uses your environment variables automatically.

Base URL

Each Space on SignalWire gets its own subdomain and each Space will have its own URLs for accessing the REST API.

All calls in the provided examples use the following as the base URL:

https://example.signalwire.com/api/laml/2010-04-01

However, please note that the actual base URL you will use will differ for each Space, since it will be customized to include your unique Space name. For your own custom URL, replace “example” with your unique subdomain.

AccountSid vs ProjectID

To support seamless migration and compatibility with other popular providers, the SignalWire Compatibility API often refers to the AccountSid. The AccountSid is a unique identifier on other providers. On SignalWire, this is known as the Project ID.

Each project within your Space gets its own, unique Project ID and this is used to authenticate requests on the API. This will be the same value as your Project ID but is set as AccountSid for compatibility.

On SignalWire’s API, the AccountSid and Project ID are the same thing.