Symfony and API Platform get “push” and real-time capabilities (Mercure protocol) is a brand new protocol allowing to push data updates to web browsers and other HTTP clients in a convenient, fast, reliable and battery-efficient way. It is especially useful to publish real-time updates of resources served through web APIs, to reactive web and mobile apps.

Both Symfony and API Platform now have an official support for this protocol!

From the ground, Mercure has been designed to work with technologies not able to maintain persistent connections. It’s especially relevant in serverless environments, but is also convenient when using PHP or FastCGI scripts.

Mercure is basically a higher-level replacement for WebSocket. Unlike WebSocket, it is compatible with HTTP/2 and HTTP/3.
It has been designed with hypermedia APIs in mind, is auto-discoverable through the Web Linking RFC and is also compatible with GraphQL.
It natively supports authorization, reconnection in case of network issue (with refetching of missed events), subscribing to several topics, topics patterns (using templated URIs)…

Because it is built on top of Server-sent Events and plain old HTTP requests, it is already compatible with all modern browsers, and requires 0 client-side dependencies.

The protocol is open (available as an Internet Draft), and a reference open source implementation of the server written in Go is available.—

HTTP/2: speed up your apps and dispatch real time updates (Symfony and API Platform’s features announcement)

HTTP/2 can improve the loading time of webpages up to 2 times. Did you know that it’s very easy to optimize your Symfony applications to leverage the advanced features of this new protocol?

This talk also contains the announcement of 3 new PHP packages:


  • a historically contextualized presentation of the different versions of the HTTP protocol;
  • a state of the protocol support in the PHP ecosystem;
  • a guide explaining how to serve your PHP and Symfony apps with h2, using Nginx, Apache and Docker;
  • many code samples showing how to use h2 to improve the loading time of your assets and APIs using the WebLink component and Twig
  • examples of how to take advantage of the protocol using the curl and Guzzle clients
  • the Mercure Protocol
  • Mercure x Symfony
  • Mercure x API Platform