Native file formats
KiCad writes all files in human readable ASCII. This makes manipulation by hand and scripting very easy.
.brd and the new
.kicad_pcb file formats are specified in this PDF (click on "download file"). The other file formats are documented (Where?).
.pro: project file. Holds few parameters that apply to the entire project (schematic and PCB layout)
.sch: schematic file
.lib: schematic symbols library file
-cache.lib: ... a local copy of all the symbols used in the corresponding schematic, so that when the folder containing a KiCad project is copied to a different PC, the schematic can still be opened and printed and will still look the same as the original draughtsperson intended – even if that other PC does not have those symbols in its main libraries (or has symbols that coincidentally have the same name but are completely different).
.000: (*) temporary file
.bak: (*) temporary file
.brd: legacy PCB layout file
.kicad_pcb: the new PCB layout file
.cmp: parts-to-module assignments file
.net(*): netlist in "Pcbnew" format ... can be regenerated by viewing the schematic file and click the "Netlist generation" button.
- "", "", "", "", "": (*) Gerber files ... can be regenerated by viewing the layout file and clicking on "Files > Plot".
(*) KiCad uses a few temporary file formats internally. The files it creates with these extensions (marked above with "(*)" ) can be excluded from version control software since they can be automatically regenerated from the source files when necessary.
Dedicated file formats
KiCad writes and reads some file formats dedicated to certain operation in collaboration with tools external to KiCad.
.dsn: SPECCTRA DSN file for autorouters (like QAutorouter, FreeRouting)
.ses: SPECCTRA session files from autorouters (like QAutorouter, FreeRouting)
Other formats used by the KiCad project
.odt: The editable source version of the help documentation is in OpenDocument word processing format.
- EDIF netlist format
.png: The W3C recommended portable network graphics format is a good format for posting a section of a schematic (or a section of a PCB layout) to a web page, so people can see it immediately in a web browser without manually "downloading" or "installing" anything.