Butterfly is queued for analysis. Crawling candidates and ranking them takes a few minutes. This page updates itself when the list exists — you can also come back later.
What is known so far comes from the other direction:
These projects were analysed and named Butterfly among their alternatives. The relationship is not symmetric — how Butterfly rates them is a separate judgement, made when Butterfly is analysed in its own right.
calls Butterfly “A direct alternative: Flutter-based handwriting note app with PDF annotation, more modern UI and strong cross-platform consistency.”
Xournal++ is a handwriting notetaking software with PDF annotation support. Written in C++ with GTK3, supporting Linux (e.g. Ubuntu, Debian, Arch, SUSE), macOS and Windows 10. Supports pen input from devices such as Wacom Tablets.
calls Butterfly “Cross-platform Flutter app with handwriting, PDF annotation, and stylus support; choose for mobile plus desktop coverage.”
Sketch and take handwritten notes.