About
LeanFPS is an MIT-licensed Windows 10/11 x64 gaming utility built with Rust and egui/eframe. It detects games, offers per-game and genre profiles, measures average FPS and 1% lows through Windows event tracing, and keeps session history. Each tweak has an explanation and an individual Undo option. Temporary session changes restore on exit; persistent settings remain until individually undone.
The free core includes game detection, FPS measurement and five tweaks. Optional Pro currently costs US$19 once. The publisher lists a 5.9 MB installer and 6.5 MB installed size. Results vary by PC and game. LeanFPS does not inject an in-game overlay or disable Defender, Memory Integrity, the firewall or Windows Update.
Full MIT source: https://github.com/Jamailar/leanfps
The attached image is the public UI preview with example data, not a benchmark.