Projects, files and offline work

A project is a folder

my-board/
  my-board.falcad              project manifest
  falcad.lock                  pinned engines and toolchains
  schematics/main.sch.json     schematic
  pcb/main.pcb.json            board
  simulation/*.sim.json        simulation setups
  firmware/src/*.ino           firmware sources
  rtl/*.v, *.sv, *.vhd         HDL sources
  .falcad/                     local state (proposals) — add to .gitignore

Files are plain, canonical JSON. Saving an unchanged design produces byte-identical files, so git diff shows only real changes. The full specification is in The .falcad format.

Where projects live

Running in	Open / save
Desktop app	any folder you choose in the system dialog
Chrome / Edge	any folder you choose (File System Access API)
Other browsers	browser storage; move projects in and out as `.falcadpack` archives

A .falcadpack is a ZIP of the project folder (Export project archive in the command palette). Opening one is always safe. Archives are checked for path tricks and decompression bombs before anything is read.

Nothing gets lost

FalCAD journals every applied edit locally as it happens. If the app or the computer stops before you save, the welcome page offers Recover unsaved work the next time you open FalCAD. If you close with unsaved changes, the desktop app asks before discarding them.

No account needed

Opening, editing, checking, simulating, compiling and exporting local projects never needs an account, a network connection or a subscription. Hosted collaboration is optional and arrives with FalCAD Cloud.