FIT manufacturers — every device maker in a .fit file, measured

Every device maker that appears in the 68,068 real .fit files this reader is tested against, and how many each wrote. A .fit file names its manufacturer in its own file_id message, so this is read from the files, not guessed from a filename.

The corpus is mostly one maker

The distribution is steep: 42 named manufacturers appear, and the counts fall away fast after the first. That is worth knowing, because a reader tuned on one maker’s files is tuned on almost the whole corpus — and the interesting behaviour lives in the long tail, where a device writes FIT in a slightly different way. 3 makers with a known reading quirk have a page of their own, linked below; the rest are listed here rather than given a page that would guess at how they behave.

Reading your own file

Whichever device wrote it, open your .fit file here — the reader runs on your machine and uploads nothing. The manufacturer pages linked above each explain the one thing that maker’s files do differently, from Wahoo’s out-of-order definitions to Zwift’s missing GPS.