Tobi from Shopify used a variant of autoresearch to optimize the Liquid template engine, and found a 53% speedup after ~120 experiments: https://github.com/Shopify/liquid/pull/2056
I wrote up some more notes on that here: https://simonwillison.net/2026/Mar/13/liquid/
How much did this cost? Has there ever been an engineering focus on performance for liquid?
It’s certainly cool, but the optimizations are so basic that I’d expect a performance engineer to find these within a day or two with some flame graphs and profiling.