A couple more notes on this:
First, the xterm.js benchmarks were very noisy. A lot of the results relied on whether they got lucky with the V8 JIT/inliner. e.g. the frame times for ASCII ranged from 20us to 100us (!!!). For the purpose of optimism, I only used the fastest times
libghostty for WebAssembly got a lot of love recently and is now very, very, very good. I spent the day building harnesses and comparing to xterm.js and here are the results: faster at IO, faster at reflow, faster at rendering. Like, a lot a lot faster.
We now provide pre-built




