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Advanced communications from the source. | SignalWire

SignalWire RELAY Mobile SDK

React Native real-time communications toolkits for iOS and Android

By Erik Lagerway, VP of Product

Go straight to the documentation for the Relay SDK for React Native

We live in a mobile world with a growing number of businesses serving mobile users. The first thing we think of in mobile real-time communications is mobile chat applications, not unlike Facebook messenger or WhatsApp. While this is a common consumer use case it’s only part of the solution businesses are looking to leverage with voice, video and messaging in their offers.

Here are some examples of how SignalWire mobile SDKs and APIs are being used for communications in business.

CRM Integrations

One of the more requested use cases we see is integrated real-time communications in various CRM (Customer Relationship Management) platforms. To be more specific, our customers are building applications based on SignalWire toolkits that allow users of those CRMs to call out to contacts and phone numbers directly from the CRM itself. Think of it as a built in phone where users simply click on the phone number to make the call. The call is then registered in the CRM as an outbound call and brings up the notes dialog so the sales or support rep can register the action and potential change in disposition.

Enterprise Communications

Users are mobile, and when they aren’t on the move they're on their laptops and need to communicate with their teams, customers, and partners. Building real-time communications features into an existing application, or creating new applications with these features, used to be a daunting task but with SignalWire, much of the heavy lifting is done for you. You can implement an enterprise communications workflow from within your existing application by using our development tools and services.

Mobile Gaming

As multiplayer gaming becomes more predominant on mobile platforms, in-game communications is an expectation. With SignalWire, game developers can integrate RELAY mobile SDKs into their game and enable voice and video communications between the players (currently limited to 1:1) to allow for a more immersive game experience.


Now that we have outlined a few use cases where this technology could be used, let’s take a quick look at the initial features, SDK resources, and an accompanying example application that is available today.

Voice & Video (1 to 1, Inbound and Outbound)

  • SIP (Voice over IP)
  • Verto / Web Browser (WebRTC)
  • PSTN (Legacy network / Phone Numbers - Voice Only)

Simultaneous Ringing and Multiple Call Paths

In the case where you have multiple media paths, like a SIP endpoint using a defined PSTN number and a Web Browser endpoint using the same PSTN number, all devices will ring until one answers the call.

Sample Application

If you have any trouble building the App, follow the steps for each native library to double check all frameworks have been linked properly:


Instructions for react-native-webrtc

Instructions for react-native-incall-manager

Instructions for async-storage


Instructions for react-native-webrtc

Instructions for react-native-incall-manager

Instructions for async-storage

Testing with a web browser client

The links below will help you test against the JavaScript sample application:

We are excited to see what you will build with these new tools; come and share your experience in the SignalWire community!

Disruptive Pricing

Our fee structure is simple: we meter per minute / per call leg. We don’t charge for setting up calls programmatically and we don't charge for securing your calls. At SignalWire, we see communication as a necessity and don't agree with egregious markups that get in the way of innovation. We believe in empowering developers and our pricing allows us to maintain this goal.

US Calling Rates:
US Inbound $0.00255
US Outbound $0.0065
SIP / WebRTC (1:1) In/Out $0.0007 

For all our disruptive pricing check here

Come and build something great on SignalWire!

Developer documentation for SIP:

Main developer documentation site:

Friendly support can be found in our online community.

P.S. We always announce features to our community before bringing it to the general public, so sign up for your free SignalWire account today and join our Community!