// the find
uNetworking/uWebSockets
Simple, secure & standards compliant web server for the most demanding of applications
µWebSockets is a C/C++ HTTP and WebSocket server library built for raw throughput — the kind you need when you're running a crypto exchange and can't afford to drop messages under load. It's header-only C++, sits on top of the µSockets abstraction layer, and has Node.js bindings via a separate repo. If you need to push tens of thousands of WebSocket messages per second with low latency, this is the serious option.
Continuous OSS-Fuzz coverage with ~95% daily fuzzing and a clean sanitizer record is rare — most C++ networking libraries don't bother, and the ones that do usually have a backlog of open issues. The pub/sub topic tree is built-in and efficient, not bolted on as an afterthought. The event-loop layer is genuinely pluggable: swap between epoll, libuv, ASIO, or GCD at compile time without touching application code. Perfect Autobahn|Testsuite score since 2016 means the WebSocket implementation actually follows the spec, which eliminates a whole class of subtle client-compatibility bugs.
The licensing situation is deliberately murky — the README says 'intellectual property, all rights reserved' and then carves out Apache 2.0 only for files where 'such explicit notice is given'. You need to audit carefully before shipping anything; the author has a history of retroactively tightening terms. Documentation is thin: the user manual is a single Markdown file, and you're largely expected to read the examples and source headers to understand behavior. No HTTP/2 support in the main library (there's an HTTP/3 stub but it's experimental), which is a real gap if you're building anything that needs server push or stream multiplexing. The threading model — one app instance per thread, shared listen socket — is sound but requires your application code to be thread-safe with no help from the library; it won't protect you from data races in your own handlers.