Training analysis that stays on your device.
Open the .fit and .gpx files your watch or bike computer records and get training load, trends, personal records and lap-by-lap detail for running, cycling and swimming. No account, nothing uploaded, free and open source.
What you get
- Today Training load against your 6-week baseline, the acute:chronic ratio, VO₂ max and recovery estimates, and a year of consistency at a glance.
- Every session in detail Heart-rate and pace timeline, per-kilometre lap tiles, streams, the route coloured by heart-rate zone, and pool swims length by length.
- Trends Weekly volume by sport, aerobic efficiency (pace at a given heart rate), intensity distribution, and pace, distance and heart-rate histograms.
- Records Best 1 km, 5 km and 10 km, longest sessions, and a critical pace curve compared with the previous period.
- Calendar Month by month with weekly totals, training load and rest days.
- Works offline Install it on your phone or computer; after the first visit it needs no connection.
Your files never leave your device
Lapline runs entirely in your browser. Your .fit and .gpx files are read on your device and saved in your browser's own storage. There's no Lapline server and no account, so there's nowhere for your data to go.
Three extras are off until you turn them on: anonymous usage statistics (which screens are used, never your data), place names for your activities (sends a start coordinate to OpenStreetMap), and weather (sends a start coordinate and date to Open-Meteo). To move to another browser, export a backup file and restore it there.
Getting your files
Lapline reads .fit and .gpx files. Here's how to get the original files out of your device's app.
More: opening a .fit file online · Garmin files without uploading · time in heart-rate zones · your critical pace curve
Questions
Is it free?
Yes. Lapline is free and open source under the MIT licence. There's no paid tier and nothing to sign up for.
Which devices does it work with?
Anything that records .fit or .gpx files: Garmin, COROS, Wahoo, Suunto, Polar, Zwift, bike computers, and Apple Watch through an export app such as HealthFit. .tcx files aren't supported yet.
Where is my data stored?
In your browser, on your device. Each browser keeps its own copy, so a different browser or computer starts empty: use Settings → Backup to export everything as one file and restore it there. Clearing your browser's data for this site deletes it.
Can I use it on my phone?
Yes. Open Lapline in your phone's browser and add it to your Home Screen. On iPhone and iPad this also matters for your data: Safari deletes a website's saved data after 7 days without a visit unless it's installed.
Is this medical advice?
No. VO₂ max, training effect, recovery time and training load are estimates for training guidance. They can be wrong and can't diagnose anything. If you have a health condition, talk to a doctor before changing your training.
Does it sync with Garmin Connect or Strava?
No, on purpose: syncing needs a server and an account. You bring the files. In Chrome or Edge on a computer you can also connect a Garmin watch's USB folder once and re-sync it with one click.