interested in networking, distributed systems and type theory. I work at Mozilla on Firefox’s networking stack, more specifically QUIC and HTTP/3. Welcome to my little island on this wondrous thing called The Internet.
Talk "A Report on Firefox's HEv3 Implementation" @IETF 126
I reported on Firefox’s Happy Eyeballs v3 implementation in the HAPPY working group at IETF 126 in Vienna. Happy Eyeballs v3 races connection attempts across address families and protocols and keeps the first one that connects. Since IETF 125 it is enabled by default in Firefox Nightly, reaching roughly 15k users. The implementation is a library of its own, mozilla/happy-eyeballs: a deterministic, sans-I/O state machine in Rust with no network and no clock. The caller drives the I/O and passes time in. It does not depend on Firefox, it embeds in Necko’s C++ event loop, and every scenario is a plain unit test. ...
Slides from the HTTP Workshop 2026
I gave three short talks at this year’s HTTP Workshop. Increase and evolve HTTP/3 & QUIC Slides: mxinden-bot.github.io/slides/04-quic-discussion A discussion deck. HTTP/3 sits around 30% and has plateaued. I cover the ways to measure that share. Then what holds adoption back: server and framework support; “security” software and enterprise middleboxes that break QUIC; and the server-side performance gap to TCP. I raise QUIC v2 as an anti-ossification concern, barely deployed. I close on the HTTP/3-native use cases (WebTransport, Media over QUIC, MASQUE) and the two ways to reach HTTP/3, Alt-Svc and HTTPS records, with the latter preferred. ...
Working Draft - HTTP/3 und WebTransport mit Max Inden
I joined the Working Draft podcast to talk about HTTP/3 and WebTransport. We traced the evolution from HTTP/1 through HTTP/2 to HTTP/3, why head-of-line blocking pushed the web toward QUIC, and how building transport and security together enables 1-RTT and 0-RTT handshakes, connection migration, and encrypted DNS. We closed on WebTransport as a modern alternative to WebSocket, supporting both streams and datagrams. The episode is in German. Thanks for having me! ...
Talk "Happy Eyeballs v3 in Firefox" @IETF 125
I presented Firefox’s Happy Eyeballs v3 implementation in the HAPPY working group at IETF 125 in Shenzhen. At that point the implementation had landed in Firefox Nightly, still off by default and reachable by flipping network.http.happy_eyeballs_enabled in about:config. It followed the draft with no major deviation. I introduced mozilla/happy-eyeballs, the Rust library behind it: deterministic, free of side effects, abstract over I/O and time, and with no dependency on Firefox. Each scenario is a plain unit test, which makes the algorithm easy to formalize. I offered those tests to the working group as a way to pin the algorithm down. ...
Talk "Intro to WebTransport - the next WebSocket?!" @FOSDEM
I gave a talk on the upcoming WebTransport protocol in the Browser Devroom at FOSDEM 2026. WebTransport is an upcoming protocol (standardized by the IETF) and Web API (standardized by the W3C) for bidirectional communication on the web. It provides multiplexed streams and unreliable datagrams on top of HTTP/3 and HTTP/2. This talk explains how WebTransport works at the protocol level, how it maps to QUIC when run on top of HTTP/3, and how its capabilities differ from WebSocket. The session will also cover the current state of browser and server support, and where the ecosystem is heading next. ...
Talk "Modern Network Protocols — What’s Next for Firefox and the Web?" @FOSDEM
Andrew, a colleague, and I presented an outlook for Firefox and the web. The Web’s transport stack is changing rapidly, with QUIC, HTTP/3, and encrypted DNS seeing broad adoption. This talk gives an overview of the modern network protocols Firefox already deploys and invests in, including QUIC and HTTP/3’s growing share of Web traffic. It will highlight what Firefox actually sends on the wire today, what benefits we observe in practice, and where the Web’s protocol landscape stands in early 2026. ...
netstack.fm - Modern networking in Firefox with Max Inden
I joined Glen on the netstack.fm podcast to talk about modern networking in Firefox. We discussed Mozilla ’s work on Firefox’s QUIC and HTTP/3 stack — improving UDP I/O, congestion control, and overall performance — and why QUIC matters as a fast, encrypted, and evolvable transport for HTTP/3, WebTransport, and beyond. Thanks for having me, Glen! https://netstack.fm/#episode-11
Fast UDP I/O for Firefox in Rust
Motivation Around 20% of Firefox’s HTTP traffic today uses HTTP/3, which runs over QUIC, which in turn runs over UDP. This translates to substantial UDP I/O activity. Firefox uses NSPR for most of its network I/O. When it comes to UDP I/O, NSPR only offers a limited set of dated APIs, most relevant here PR_SendTo and PR_RecvFrom, wrappers around POSIX’s sendto and recvfrom. The N in NSPR stands for Netscape, giving you a hint of its age. ...
Talk "Fast UDP makes QUIC quicker - optimizing Firefox’s HTTP3 IO stack" @FOSDEM
I presented my recent work on Firefox’s HTTP3/QUIC stack in the Network Devroom at FOSDEM 2025. QUIC is a new transport protocol on top of UDP, transporting a large portion of the Internet traffic today. UDP I/O performance is crucial for QUIC implementations, where e.g. system call overhead can significantly impact throughput at high network speeds. To improve QUIC throughput, Firefox is switching to a modern UDP IO stack in Rust, using mechanisms like recvmmsg, and GRO across Linux, Windows, and Android. ...
Stepping down as a (rust-) libp2p maintainer
I don’t see myself making major contributions to (rust-) libp2p in the near future and thus I am stepping down as a maintainer. As announced before, I have left Protocol Labs in December 2023. After a 2 month re-orientation break, I have decided to move on entirely. My first commit was 5y ago, a small bug fix in our address handling. Since then lots happened. A couple of milestones I was involved in: ...