Velosyn

Turn every ride into insight. Velosyn records your GPS tracks with rich motion data and turns them into clear trip summaries; no accounts, no tracking, all on device.

Velosyn — Insights, not data

Velosyn isn't another GPX viewer. It's an on-device analysis engine that turns every ride, hike, drive, or sail into something you can actually learn from.

Most GPX apps stop at drawing a line on a map and plotting the raw numbers from the file. Velosyn starts where they stop. It cleans the noisy signals your GPS produces, reconstructs what really happened during your trip, and surfaces the moments that matter — the hardest climb, the fastest descent, the segment where you finally beat your previous best.

What makes Velosyn different

• Physics-based signal cleaning. Raw GPS speed is jittery and misleading. Velosyn runs a custom pipeline that filters the signal and derives honest acceleration and deceleration metrics from it.

• Real grade estimation. Climbs and descents are computed from the track geometry itself, not just read blindly from the file. Steep sections, rolling terrain, and false flats become visible.

• Personal records and week-over-week trends. Every imported or recorded track is indexed into a local database, so you can see your progress across your entire history — not just one trip at a time.

• Device signature detection. Velosyn recognizes which recording device or app produced a GPX file from its metadata, so you know what you're looking at.

• Live activity recording with real-time analysis. Start a recording and watch metrics evolve as you move, with a Live Activity on the Lock Screen and Dynamic Island.

• Batch analysis with intelligent caching. Drop in a folder of tracks and Velosyn indexes them in the background, remembering results so re-opening a trip is instant.

Built for anyone who moves

Cyclists tracking training. Hikers logging trails. Sailors reviewing passages. Off-roaders analyzing runs. Drivers curious about a road trip. If it produces a GPX file, Velosyn has something to say about it.

Beautiful maps, your choice

Pick from OpenStreetMap, CARTO Voyager, OpenTopoMap, OpenSeaMap, Esri satellite and topo, Wikimedia, CyclOSM, and more. Light styles, dark styles, terrain, marine — whatever fits the trip.

Private by design

No account. No sign-up. No cloud sync. No analytics SDK. No advertising. No tracking.

Everything Velosyn does — recording, analysis, personal records, indexing — runs entirely on your device. Your tracks never leave your iPhone unless you choose to export them via the standard iOS share sheet.

Import, export, keep your data yours

Open any .gpx file from Files, Mail, Messages, or anywhere else with the standard iOS share sheet and Velosyn will import and analyze it automatically. Export any track back out as a clean .gpx file at any time.

Permissions, briefly

• Location (while using / background): so recording continues while your screen is off. Used only for your own trip; never sent to us. • Motion & Fitness: so accelerometer and gyroscope data can be embedded in your GPX for richer analysis.

Made by an independent developer

Velosyn is written from scratch in Swift by a single developer who wanted a GPX tool that actually thought about the data instead of just displaying it. Feedback, bug reports, and feature requests are read personally and shape where the app goes next.

Insights, not data. Give your trips the attention they deserve.