RELAY Resource Center

Get running with RELAY, the protocol built for telecom

Jul 14, 2022

If you are familiar with SignalWire products or even caught our first introduction to RELAY, you know we’ve been building RELAY for a while now. But do you know what it’s all about, and do you appreciate just how awesome it is? RELAY is a real-time web service protocol that maintains persistent, asynchronous connections to the SignalWire network. Our RELAY APIs use WebSocket technology, which allows for simultaneous, bi-directional data transmission. This is in contrast to traditional REST APIs that rely on one-way communication. In layman’s terms, RELAY is like talking over a telephone where you can indiscriminately talk and hear simultaneously. REST is like talking over a walkie-talkie or CB radio where only one person can speak at a time. So, if you want to consume every event that is going on in your application, there is no substitute for RELAY!


Our recent announcement about the integration of RELAY in one SDK inspired a host of new guides to demonstrate the power and flexibility of RELAY. All of our demos are built using SignalWire’s RELAY SDKs. Let’s look at some of the resources in our most popular namespaces.

  

📞 Voice

Phone Call

Voice is all about phone calls, whether that be a one-to-one connection between VOIP numbers, a SIP connection, or a complex IVR call center. If you aren’t already a pro at these telecom terms, our article “What is SIP?” is a great place to start. If you are a telecom veteran, you can try RELAY with the simplest use cases:

  • Making and Receiving Phone Calls shows you how to configure your SignalWire Space to start making and receiving calls with a Node.js application.

  • Call Forwarding shows you how to configure your SignalWire Space to forward incoming phone calls with a RELAY Consumer.


Then check out more advanced use cases:

  • Weather IVR demonstrates a simple IVR application that uses the SignalWire Realtime SDK to provide current weather reports to the caller in Washington DC by either a phone call or text.

  • Appointment Reminder IVR creates a service to send custom text-to-speech calls to any number and uses user input to confirm or deny appointments. You can receive real-time information about their selection and programmatically redirect their call.

  • Translating and Transcribing Voice Calls uses a RELAY SDK and the Google Cloud Speech and Translate APIs. Receives an incoming call, then translates it and displays the incoming call number, a translation text of the audio, and an element to play the original call audio.


📱 Messaging

Appointment Reminder

Messaging encompasses SMS and MMS in a peer-to-peer (P2P) or application-to-person (A2P) capacity. Before starting any application development, you should check out our information on The Campaign Registry (TCR). After your phone numbers are cleared to send messages, you can start employing RELAY for some simple use cases:

  • Sending and Receiving Messages shows you how to configure your SignalWire space to start sending and receiving SMS messages with a Node.js application.

  • Forwarding SMS to Email walks through making a webhook to forward messages to an email address and configure it in your SignalWire space.


After you’ve mastered the basics, there are examples of more advanced use cases:


You can even utilize RELAY for administration purposes:


🎥 Video

Programmable Video Conference

SignalWire Video products have often featured in our recent news as we have rolled out Programmable Video Conferences. We now offer a couple of distinct options for developing an app with videoconferencing.

The first is our newer product Programmable Video Conferences (PVC). This option for integrating videoconferencing works right out of the box and includes customization options. This product is so easy to use that everything you need to know is in a couple of resources:


The second path with video development is to use SignalWire’s Video SDK to build a complete video conferencing application from scratch with granular control over every feature. Start here for the basics:

  • First Steps with Video walks through creating and joining a simple video room with the Video API.

  • Simple Video Demo adds functionality to a simple video room using events and creates a backend server to proxy video room token requests.


There are many examples of advanced use cases to follow or get inspiration from:


💬 Chat

Chat with React

Finally, our Chat namespace allows you to incorporate a chat feature in your applications. Our Chat Overview explains how Chat is built on a basic PubSub base. Chat adds an element of members to PubSub, but is still a very straightforward product for simple use cases:

  • First Steps with Chat describes how to get a Chat token, subscribe to channels, and listen for message events.

  • Simple Chat Demo adds to "First Steps with Chat" with a simple UI, the ability to download existing messages, and even a typing indicator using member state.


For inspiration from slightly more advanced use cases:

  

Let's get to it!

All of these products are available to you individually, but—like gaming combos—they become even more powerful when used together. SignalWire is always improving our RELAY products and platform so that you can build powerful, dynamic, and reliable applications. These resources may include the answer to your development needs, or you can find inspiration for your next innovation. If you create something cool, remember to submit it to the Code Bounty! Happy Coding!