FilmKit is a browser-based preset manager and RAW converter for Fujifilm X-series cameras, built as a static client-side app hosted on GitHub Pages. The tool connects directly to cameras using WebUSB, allowing users to manage presets, convert RAW files, and preview film simulations without installing software. FilmKit works with X100VI and likely supports other X-series models like X-T5 and X-H2.

Unlike Fujifilm's official X RAW STUDIO, FilmKit offers faster preset management through better camera work queue handling and a non-locking UI. Users can read, edit, and write custom presets directly on their camera, save presets locally, and drag-and-drop between camera and computer storage. The app also features automatic preset detection when loading RAF files and supports mobile access via phone browsers.

The project was reverse-engineered from Fujifilm's proprietary protocol using Wireshark USB captures of X RAW STUDIO communication. FilmKit implements Picture Transfer Protocol (PTP) operations to read and write preset properties, handling the camera's complex encoding schemes for parameters like HighIsoNR and color temperature. While currently tested only on X100VI, the developer welcomes community contributions through bug reports and Wireshark capture submissions to expand camera compatibility.