TrailFix: GPS Toolkit
Most GPS apps solve one of two problems: planning your adventure or navigating it. TrailFix solves what happens in between. It’s the compatibility and reliability layer — the step between your planning app and your device where routes get converted, files get cleaned, and everything gets prepared so it actually works when you’re standing at the trailhead.
The gap in the GPS ecosystem
Route planning tools like Gaia GPS, Komoot, and Ride with GPS are excellent at what they do. So are navigation devices from Garmin and Wahoo. Between them sits a file preparation step that’s historically been handled by desktop tools, web utilities, or features buried inside other apps like Garmin BaseCamp. TrailFix is the mobile-native bridge — purpose-built for that step, designed to take less time than the ride you’re planning.
Five tools. One app. Every one of them exists because a specific, common problem causes real-world navigation failures.
- Convert — routes leave the calculation up to your device; tracks lock in the exact path. Converting means your GPS follows the road you chose, not the one it thinks is faster.
- Simplify — GPS devices have point limits; large files from planning apps frequently exceed them and get rejected.
- Reverse — out-and-back planning and return trips are a constant real-world need.
- Repair — GPS files accumulate errors over their lifetime: duplicate points, drift spikes, elevation anomalies that cause mid-ride navigation failures.
- Export — GPX, KML, and TCX are not interchangeable; the format that works with Garmin may not work with Wahoo, CalTopo, or REVER.
The design
The landing screen keeps friction near zero. Drag a file in, choose from Files or cloud storage, or tap a recent file. TrailFix reads GPX, KML, and TCX and immediately renders routes, tracks, and waypoints on a map — so you know what you’re working with before you change anything.
From there, the tools are available via a scrollable card tray at the bottom of the screen. Tap a card to open a bottom sheet with that tool’s settings. Every change renders live on the map, overlaid on the original path in a distinct color. Both lines are visible simultaneously — original and modified — so you can see the effect of each operation before committing. Save, revert, or keep working. Export covers GPX, KML, or TCX and shares directly to Files, AirDrop to your GPS unit, or any app. Your original file is never modified.
No configuration required for Repair — the app auto-scans on open and flags issues. One tap fixes them. The design principle throughout is confidence before commitment: see the change, then decide.
What this is built on
TrailFix is a ground-up rebuild of the original GPX Converter app — new architecture, new design, and a substantially expanded scope. It’s written in Swift and SwiftUI with a custom SAX-based GPX parser and the RDP algorithm implemented from scratch for track simplification. The name and structure are intentional: a toolkit, not a converter, leaving room for future tools — route merging, waypoint management, elevation editing, device-specific optimization — without repositioning.
The motivation is the same as the original: planning a backroad route on the KTM and then fighting with file formats to get it onto the GPS in a form that actually works. Sometimes you build the tool you wish existed.
How this came together
TrailFix went from concept to a polished, shippable app in a matter of weeks — the kind of timeline that wouldn’t have been realistic for a solo developer-designer even recently. That speed reflects a workflow worth acknowledging: tight integration between Figma and Claude compressed the distance between design decisions and working UI in ways that are genuinely new. Components were designed, interrogated against the actual use cases, and refined in a loop that’s materially faster than the traditional handoff model.
This kind of AI-assisted workflow is moving fast — what’s accelerated today will be the baseline tomorrow. What it produced here is the relevant fact: a complete, native iOS toolkit that reflects the same design-forward thinking as the larger product strategy work Signal Strength does for clients.