Mercure in a Few Words

• native browser support, no lib nor SDK required (built on top of HTTP and server-sent events)
• compatible with all existing servers, even those who don't support persistent connections (serverless architecture, PHP, FastCGI...)
• built-in connection re-establishment and state reconciliation
• JWT-based authorization mechanism (securely dispatch an update to some selected subscribers)
• performant, leverages HTTP/2 multiplexing
• designed with hypermedia in mind, also supports GraphQL
• auto-discoverable through web linking
• message encryption support
• can work with old browsers (IE7+) using an EventSource polyfill
• connection-less push in controlled environments (e.g. browsers on mobile handsets tied to specific carriers)

The reference hub implementation:

• Fast, written in Go
• Works everywhere: static binaries and Docker images available
• Automatic HTTP/2 and HTTPS (using Let's Encrypt) support
• CORS support, CSRF protection mechanism
• Cloud Native, follows the Twelve-Factor App methodology
• Open source (AGPL)