What is Mercure used for?

Mercure is a protocol and Go reference hub for pushing real-time updates to browsers and other HTTP clients, for apps built on web APIs. It is a good fit for live updates for reactive web apps, pushing API changes to mobile clients and real-time notifications.

Is Mercure open source?

Yes. Mercure is open source under the AGPL-3.0 licence. Its source code is on GitHub at dunglas/mercure and is written mainly in Go.

Yes. Mercure is open source, so the software itself is free to use. A managed cloud version is also available, with paid plans from €30 per month.

Can I self-host Mercure?

Yes. Mercure can be self-hosted on your own server or infrastructure.

What is Mercure an alternative to?

Mercure is an open-source alternative to Pusher, Ably and PubNub. Other open-source alternatives to Pusher include Deepstream.io and Centrifugo.

Is Mercure actively maintained?

Yes. The most recent commit to Mercure was on 25 September 2026, and the latest release is v1.0.2, published on 25 September 2026. The project has 5.3k stars on GitHub.

Mercure: open-source alternative to Pusher, Ably, PubNub

About Mercure

Mercure is a protocol that lets servers push updates to browsers and other HTTP clients without polling, while staying light on battery. It is especially useful for publishing asynchronous, real-time updates to resources served through web APIs, so reactive web and mobile apps can react as data changes.

The repository contains both the protocol, which is also published as an Internet-Draft, and a production-grade reference implementation of a Mercure hub, the server component. The hub is written in Go and is built around Server-Sent Events. A Go library lets applications implement the protocol directly without running a hub, and an official Docker image is provided.

Mercure is free software under AGPL-3.0, created by Kévin Dunglas and sponsored by Les-Tilleuls.coop. Teams that prefer not to operate the hub can use the managed, high-scalability version offered through Mercure.rocks, and the project provides a getting-started guide, full documentation and a demo.

Key features

Real-time push updates over HTTP
Reference hub server written in Go
Go library to embed the protocol
Official Docker image
Server-Sent Events support
Internet-Draft protocol specification

Good fit for

→Live updates for reactive web apps
→Pushing API changes to mobile clients
→Real-time notifications

Built with: Go; GraphQL
Tags: realtime; server-sent-events; push; streaming; api; go; docker; protocol

Mercure: questions and answers

What is Mercure used for?: Mercure is a protocol and Go reference hub for pushing real-time updates to browsers and other HTTP clients, for apps built on web APIs. It is a good fit for live updates for reactive web apps, pushing API changes to mobile clients and real-time notifications.
Is Mercure open source?: Yes. Mercure is open source under the AGPL-3.0 licence. Its source code is on GitHub at dunglas/mercure and is written mainly in Go.
Is Mercure free?: Yes. Mercure is open source, so the software itself is free to use. A managed cloud version is also available, with paid plans from €30 per month.
Can I self-host Mercure?: Yes. Mercure can be self-hosted on your own server or infrastructure.
What is Mercure an alternative to?: Mercure is an open-source alternative to Pusher, Ably and PubNub. Other open-source alternatives to Pusher include Deepstream.io and Centrifugo.
Is Mercure actively maintained?: Yes. The most recent commit to Mercure was on 25 September 2026, and the latest release is v1.0.2, published on 25 September 2026. The project has 5.3k stars on GitHub.