What is autopush-proxy-poc?

Web push notifications work through relay servers that sit between websites and browsers. Mozilla operates such a service for Firefox, and the "Autopush Interceptor" is a proof-of-concept project that lets you run your own version of that relay server instead of relying on Mozilla's. This matters if you want full control over how push notifications are delivered to your users, for example, if you're building a privacy-focused product, operating in a regulated environment where data must stay on your own infrastructure, or just want to understand how the push pipeline works. The server handles two sides of the push equation. On the websocket side, it accepts connections from browsers, responding to "hello" and "register" requests so that a browser can subscribe to push notifications through your server instead of the default. On the ingestion side, it decodes and verifies the cryptographic headers (VAPID) that websites send to authenticate their push messages, and it handles the key exchange (ECDH) needed to route messages to the right browser. A couple of pieces are still unfinished: unregistering subscriptions and relaying official broadcasts aren't implemented yet, and end-to-end encryption verification is marked as a work in progress. To use it, you run the server and point Firefox at it by changing a browser preference to your server's URL. You need to use a secure websocket connection (wss://) unless you explicitly enable insecure connections for testing. This is built in Rust and is explicitly a proof of concept, so it's more of a learning tool or starting point than something you'd put in production today. The README doesn't go into detail about performance, scaling, or deployment considerations, which reinforces that this is early-stage experimentation. Anyone considering it should understand the security implications of running a custom push relay, especially since parts of the encryption and verification flow are still incomplete.