What is Socket.IO?
Socket.IO is a library created in 2010 that provides realtime, bi-directional communication between clients and servers. It allows the management of connections, sending and receiving messages, and more. Built on top of the WebSocket protocol, it provides additional capabilities compared to raw WebSockets. WebTransport (a WebSocket alternative) is also supported.
6 alternatives to Socket.IO to consider
We’ll now look at alternatives to Socket.IO - competing technologies that allow you to build realtime experiences for end-users.
Azure SignalR Service
Azure SignalR is an Azure-hosted, fully managed realtime framework built on top of an open-source software library for Microsoft ASP.NET. It allows server code to send asynchronous notifications to client-side web applications. The library includes server-side and client-side JavaScript components.
Firebase
Firebase is a cloud-native backend by Google that allows developers to build mobile and web applications. Firebase services include Firebase Realtime data, Firestore database, authentication, and Firebase Cloud Messaging (FCM), among others.
PubNub
PubNub is a developer API platform that powers the realtime infrastructure in apps to build engaging Virtual Spaces where online communities can connect. It can serve as the foundation for online chat, live events, geolocation, remote IoT control, and realtime updates.
Pusher
Pusher is a managed pub/sub messaging service that provides hosted APIs and SDKs for adding realtime features to web and mobile applications. Pusher’s offers two products:
- Channels: WebSocket pub/sub messaging
- Beams: Programmatic push notifications for mobile and web
Microsoft Azure Web PubSub
Microsoft Azure Web PubSub is a fully managed service for real-time messaging using WebSockets and the publish-subscribe pattern. It handles up to 100,000 concurrent connections, managing scaling, encryption, and authentication. It's ideal for live broadcasts, IoT dashboards, and integrates with Azure functions. It provides APIs for managing clients and messaging.
Ably
Ably is the definitive realtime experience platform of the internet, serving more WebSocket connections than any other pub/sub platform. Our product suite places composable realtime in the hands of developers. Simple APIs, use case specific SDKs and pre-built integrations, enables the creation of a host of live experiences - including live updates, chat, collaboration, notifications and fan engagement - with no infrastructure to build.
Key Ably features and capabilities
- Ably is underpinned by a globally-distributed network of datacenters and edge acceleration points of presence.
- Ably‘s SDKs provide a consistent and idiomatic API across a variety of supported platforms.
- Connect with pre-built integrations for Webhooks, Lambdas, databases, cloud services, observability tools and stream processors.
- Build the ultimate realtime app with our feature rich suite of products - Pub/Sub and notifications, Chat, LiveObjects, LiveSync, and Spaces.
- Guaranteed message ordering and delivery.
- Global fault tolerance and a 99.999% uptime SLA.
- 6.5ms round trip message delivery latency.
- Elastic scalability to handle millions of concurrent clients.
- Consumption-based, per-minute-billing, built for scale. Ably not only enables you to make the most of your budget, but also enjoy greater flexibility, faster build times and a quicker ROI.
Disclaimer: The information on the alternatives presented here was based on documentation and resources freely available online and was last updated on 12 Aug 2026. Be sure to double-check everything before you make any decisions. If you do find anything incorrect or out of date, then please let us know.
Try Ably for free to discover the benefits for yourself
Ably has built reliable realtime infrastructure so you don’t have to. On our free plan you benefit from:
- 6M monthly messages
- 200 concurrent channels
- 200 concurrent connections
