Repair a broken activity file
Your file never leaves your device — conversion happens here in your browser.
Strava's uploader is fairly relaxed about file format compared to some platforms — it accepts GPX, TCX, and FIT without much fuss. When an upload fails or an activity shows up looking wrong afterward, the cause is almost always the data inside the file rather than the format itself. Timestamps that jump backward, GPS points that would require traveling at an impossible speed, or a file that got truncated mid-write are exactly the kind of thing Strava's own anti-cheating speed filters and upload validation are built to catch, and they'll flag or reject the file rather than accepting garbage. This is a data-quality problem, not a structural one, which is precisely what FitFileHub's repair tool is built to find. It scans the file for out-of-order timestamps and reorders them, sustained implausible-speed segments and removes them, isolated GPS spikes that throw off your pace graph, and duplicate points that can make short stretches of a route look frozen or teleporting. Every defect is listed before anything is touched — if the file already looks clean, it says so rather than making changes for the sake of it. You choose which fixes to apply, then download the corrected file to try the upload again. A genuinely corrupted or truncated file — one with a garbled header from an interrupted save or an earlier bad conversion — gets caught too, since a header that's damaged enough will stop Strava from reading the file at all. Nothing you upload here goes anywhere near a server; the whole process runs in your browser, which is worth knowing if your first instinct was to try some random online "GPX fixer" site instead. Free up to 25 MB per file, three files at a time.
Questions
Why does Strava reject a file that looks totally normal?
Strava checks the data itself, not just the format. Backward-jumping timestamps or GPS points implying an impossible speed can trigger a rejection or an anti-cheating flag even though the file opens fine elsewhere.
My Strava activity uploaded but the pace or map looks wrong — why?
This usually means the upload succeeded but the underlying data has issues like GPS spikes or duplicate points that distort pace and route rendering without stopping the upload outright.
Will fixing implausible-speed segments delete real parts of my activity?
It removes only the specific points identified as physically implausible, not entire segments of your ride or run — you see exactly what's flagged before choosing to apply the fix.
Is it safe to run my activity file through a browser tool before uploading to Strava?
Yes — the file is processed entirely client-side and never leaves your device, so there's no privacy trade-off compared to uploading it to an unknown third-party fixer site.