SHOW HN: Built GPX Monster: Browser-based tool to merge multi-day route files

2 dnl23 1 8/4/2025, 3:40:55 PM gpxmonster.com ↗

Comments (1)

dnl23 · 5h ago
I've been route planning for outdoor activities and kept running into a problem: multi-day routes online (hiking, biking) are always split into separate daily GPX files, but I need them as single tracks for planning software. Existing solutions required desktop installs or server uploads with processing delays. So I built GPX Monster - runs entirely in the browser with no server interaction. Technical approach:

Pure client-side JavaScript GPX parsing and merging Real-time map rendering as files are added Automatic chronological sorting via timestamps Live elevation/distance calculations Local file processing only - no data leaves the browser

The UX difference is immediate feedback: drag files in one by one and watch the route build on the map instantly, versus upload-wait-download workflows. Built this over a weekend to solve my own problem. Curious if others have hit this use case or have thoughts on the approach.