uWebSockets

Firebase is a cloud service designed to power real-time, collaborative applications. Simply add the Firebase library to your application to gain access to a shared data structure; any changes you make to that data are automatically synchronized with the Firebase cloud and with other clients within milliseconds.

It enables real-time bidirectional event-based communication. It works on every platform, browser or device, focusing equally on reliability and speed.

It is a simple to use, blazing fast, and thoroughly tested WebSocket client and server implementation.

SignalR allows bi-directional communication between server and client. Servers can now push content to connected clients instantly as it becomes available. SignalR supports Web Sockets, and falls back to other compatible techniques for older browsers. SignalR includes APIs for connection management (for instance, connect and disconnect events), grouping connections, and authorization.

Pusher is the category leader in delightful APIs for app developers building communication and collaboration features.

Cloud Pub/Sub is a fully-managed real-time messaging service that allows you to send and receive messages between independent applications. You can leverage Cloud Pub/Sub’s flexibility to decouple systems and components hosted on Google Cloud Platform or elsewhere on the Internet.

Supabase is currently in early-Alpha .It is an open-source Firebase alternative. It adds realtime and RESTful APIs to your PostgreSQL database without a single line of code.

Unlike traditional enterprise messaging systems, NATS has an always-on dial tone that does whatever it takes to remain available. This forms a great base for building modern, reliable, and scalable cloud and distributed systems.

PubNub makes it easy for you to add real-time capabilities to your apps, without worrying about the infrastructure. Build apps that allow your users to engage in real-time across mobile, browser, desktop and server.

It is built as a module for the Nginx web server. It can be configured as a standalone server, or as a shim between your application and hundreds, thousands, or millions of live subscribers. It can buffer messages in memory, on-disk, or via Redis.

It is a framework for building service-oriented applications. Using this, you can send data as asynchronous messages from one service endpoint to another. A service endpoint can be part of a continuously available service hosted by IIS, or it can be a service hosted in an application.

Ably offers WebSockets, stream resume, history, presence, and managed third-party integrations to make it simple to build, extend, and deliver digital realtime experiences at scale.

GUN is a realtime, decentralized, embedded, graph database engine.

SocketCluster is a fast, highly scalable HTTP + realtime server engine which lets you build multi-process realtime servers that make use of all CPU cores on a machine/instance. It removes the limitations of having to run your Node.js server as a single thread and makes your backend resilient by automatically recovering from worker crashes and aggregating errors into a central log.

SurrealDB is a newsql multi-model database, that operates in schemafull or schemaless mode, with tables, inter-document record links (no JOINs), and graph database modelling functionality.

Scalable Server for Realtime Web Apps with JSON structures that can be read, manipulated and listened to, messages that can be sent to one or more subscribers, and request response workflows, between two clients or servers.

It unlocks a new world of creativity for game developers by providing a cross-platform "backend-as-a-service" built exclusively for games. We give game developers the tools, technologies, and know-how they need to have a trouble-free launch day, and profitable day-to-day operations after that.

It is an open source backend for your next SaaS and mobile app in 1 file. It could be used as a standalone app or as a Go framework/toolkit that enables you to build your own custom app specific business logic and still have a single portable executable at the end.

A cloud service designed to power enterprise-grade web and mobile applications that require support for large numbers of users, complex data and transactional requirements, comprehensive role-based security and a modern look-and-feel.

Back4app accelerates backend development, improves development productivity, reduces time to market, and let you scale applications without managing infrastructure.

Faye is a set of tools for simple publish-subscribe messaging between web clients. It ships with easy-to-use message routing servers for Node.js and Rack applications, and clients that can be used on the server and in the browser.

Xano is a unified backend that combines database, logic, APIs, integrations, auth, and agent orchestration on managed, auto-scaling infrastructure, so developers can build and deploy without backend sprawl.

Horizon provides a complete backend that makes it dramatically simpler to build, deploy, manage, and scale engaging JavaScript web and mobile apps. Horizon is extensible, integrates with the Node.js stack, and allows building modern, arbitrarily complex applications.

It is a web server to push data to a browser, without the browser explicitly requesting it. It is an umbrella term, encompassing multiple techniques for achieving this interaction.

It is a file formats API provider, provides .NET, Java, Android, SharePoint, Reporting Services, and cloud-based APIs for document generation, conversion, and automation.

It is a development and runtime platform which simplifies and shortens mobile application development process. The platform removes the need to develop backend functionality by providing reusable server-side services via APIs. The APIs are packaged into native libraries available for all major client-side environments - Andoid, iOS, JavaScript, .NET, ActionScript and REST. The default backend logic can be modified with custom server-side code. The platform is available as an online service and a downloadable Enterprise product which can be deployed in any environment.

It is a complete and mature solution for both the stateless and stateful components of your backend.

Build better apps faster.

Pushpin is a reverse proxy server that makes it easy to build realtime web services. The project is unique among realtime push solutions in that it is designed to address the needs of API creators.

It is a blazing fast, universal web app backend for making realtime single page apps. Delight your end-users with superior speed and the lowest latency.

Telepat is an open-source backend stack, designed to deliver information and information updates in real-time to clients, while allowing for flexible deployment and simple scaling.

Syncano is a backend platform to build powerful real-time apps more efficiently. Integrate with any API, minimize boilerplate code and control your data - all from one place.

It is a technology company that provides web analytics and content optimization software for online publishers.

Fanout makes it easy to build realtime APIs and apps. The product is a cross between a reverse proxy and a message broker. Receivers subscribe to channels, and published data is delivered in realtime.

Kinto is a lightweight JSON storage service with synchronisation and sharing abilities.

It is a hosted realtime DB with RESTful APIs and supporting libraries in JS, NodeJS and Go

Simperium is a new kind of data layer. As your app reads and writes data, Simperium circulates that data everywhere it's needed. You add a Simperium library to your app and initialize it. This library keeps a persistent connection to the Simperium hosted service. The Simperium libraries and service work together to efficiently move data around for your users.

It is a fully-featured event store and message store implemented in PostgreSQL for pub/sub, event sourcing, and evented microservices applications.

We take care of complex realtime infrastructure problems so you can focus on what you enjoy - building awesome apps.

It is a cross-platform peer-to-peer database that allows apps to sync with and even without internet connectivity. Install Ditto into your application, then use the APIs to read and write data into its storage system, and it will then automatically sync any changes to other devices.

Radar is built on top of engine.io, the next-generation backend for socket.io. It uses Redis for backend storage, though the assumption is that this is only for storing currently active data.

Firehose is both a Rack application and JavaScript library that makes building real-time web applications possible.

It is an open-source (MIT-licensed) platform for session-lived backends. With Spawner, you provide your backend as a container image (aka Docker image), and Spawner gives you a private HTTP API for “spawning” new instances of that backend in your cluster. The API returns a URI, which can then be used to open HTTP connections directly to that new backend, directly from your frontend code.

It offers APIs for projects to handle authentication, email sending, file upload, image upload and processing and more in one service with a nice admin interface. It can be used as a service or self-hosted.

It is a fully hosted solution and complete toolkit to modularly embed collaborative experiences into your product remarkably fast.

Streamdata.io is a real-time cache proxy allowing you to poll JSON REST APIs and push updates to clients. Streamdata.io also keeps a history of modifications that occur on the data between two pollings. This way, streamdata.io is able to give you the list of modifications which happened since last time you fetched the data.

It is an open-source backend based on Node.js, Redis and MongoDB made for game/web/apps developers. It's scalable enough to cover thousands of requests per second, tens of thousands DAU, and provide a comfortable realtime multiplayer for a growing player base.

It is a back end as a service with geospatial capabilities. Spend more time building custom features that solve customer problems, and less time designing and maintaining back-end systems.

Complete platform for Event Sourcing & CQRS. Build fast, scalable and secure event-driven systems using any language. No more managing storage infrastructure or databases.

It allows you to connect to Entity Framework through SignalR and get updates on subscribed data in real time. This lowers the number of refreshes done by the user and ultimately allows you to do more with fewer servers.