About Stamptivity

Stamptivity is a set of free, browser-based tools for cyclists and runners — turning GPX and FIT files into GPS video overlays, stats images, and detailed activity reports. No account, no uploads: everything runs on your device.

Why it exists

Most tools that do this either cost money, require an install, or send your activity data to a server you don't control. Stamptivity is built the other way: the browser is powerful enough to decode GPX/FIT, render video overlays, and crunch zones and splits entirely client-side — so it does, and your files never leave your device.

What's included

• Overlay — live speed, map, and elevation gauges on your ride or run video
• Stamp — shareable stats images from a GPX or FIT file
• Analyze — zones, splits, best efforts, and segment detection
• Compare — two activities side-by-side with synced charts
• Merge and Convert — combine or reformat GPX/FIT files
• Retime — shift GPX/FIT timestamps to sync GPS with video
• Bike Fit — saddle height, stem length, and reach from four measurements

Who's behind it

Stamptivity is built by forgent.id.

Contact

Questions, bug reports, or feature requests — email [email protected], or use the Feedback button in the app footer for something specific to a tool you're using.

For how we handle your data, see the Privacy Policy.