Developer ships Go networking library fib, almost entirely written by Claude

On October 3, 2026, developer lesismal posted on V2EX about fib, a newly open-sourced Go networking library. According to the post, nearly all of fib's code was generated by Claude, while the main body of the post itself was edited by hand. fib supports TLS, HTTP 1/2/3 and WebSocket. The author also noted that nbio, a library he had previously written by hand, is no longer worth maintaining and has been abandoned, because he lacked the time to hand-write HTTP 2/3 support.

By the author's account, in benchmarks run through GitHub Actions CI, fib delivered several times the throughput of the Go standard library in some scenarios while using less memory. He also said it generally outperformed fasthttp, fiber and herz, libraries known for their performance. Compared with some C/C++/Rust libraries, he wrote, fib can come close to or even surpass them; in certain cases such as Pipeline/Multiplex, thanks to what he described as good backpressure optimization, fib leads some C/C++/Rust libraries by a wide margin and outpaces other Go libraries several times over.

The author cautioned that different hardware specifications, test parameters and framework configurations can produce different results. The post's wording on that point is cut off, so no further detail is available. The only checkable public information so far is this post and its summary; the benchmark numbers come from the author's own CI environment, and the material contains no report of third-party reproduction or independent evaluation.