Open source · Free forever

Train smarter.
Paddle faster.

The open-source companion app for kayak ergometer athletes and coaches. Live metrics, structured programs and deep workout analysis — right on your Mac or PC.

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macOS Windows

Companion app made for

KayakFirst Bull Kayak Ergometer

KayakFirst Bull kayak ergometer — the paddle machine KayakFit is built for

KayakFit pairs over Bluetooth with the KayakFirst Bull kayak ergometer.

Shop the Bull at KayakFirst

One session, every metric

Your paddling and your heart rate, together

KayakFit reads the KayakFirst Bull and your heart-rate monitor at the same time and merges both streams into one live session. That combination is the real payoff — you see the effort you put in next to the output you get back, second by second.

  • Live BPM right beside speed, stroke rate & power
  • Time-in-zone and effort-vs-output on one shared axis
  • A single Strava upload with power and heart rate merged
KayakFirst Bull Speed · distance · power Stroke rate · pull force Heart-rate monitor BPM Upload KF KayakFit PACE 2:14 HR 163 PWR 184 Strava Upload activity

Features

Everything you need on the water

From your first stroke to the post-session breakdown — KayakFit keeps every metric in one clean, fast app.

Deep performance analysis

Every session gets a detailed summary: stacked charts for speed, power, heart rate, cadence and pull force on one shared time axis. Hover for exact values, review time in each HR zone, and dig into per-lap splits.

  • Multi-metric synced charts
  • Per-lap splits & time-in-zone
  • Estimated power modelling

Structured training programs

Run interval sessions like 4 × 500 m / 1:00 rest or a 2 km time trial with a live step panel, countdowns and audible cues on every phase change. Each interval becomes its own lap on Strava.

  • Built-in & custom interval presets
  • Audible cues on phase changes
  • Auto-pause, auto-laps & crash recovery

Guided setup & Strava upload

A short first-run wizard connects your KayakFirst Bull over Bluetooth and, optionally, a heart-rate strap. Every session is saved as CSV and FIT, then uploaded to Strava — automatically or on demand.

  • Bluetooth pairing in seconds
  • CSV + FIT export
  • Secure Strava tokens in your OS keychain

Real-time target coaching

Give any interval a target — a heart-rate zone, pace per 200/500/1000 m, watts or stroke rate — and KayakFit checks your live effort against it. A clear badge tells you On target, Too hard or Too easy, with an audible cue the moment you drift out of range.

  • Targets by HR zone, pace, power or stroke rate
  • Live on-target badge with sound alerts
  • Short grace period keeps it from flickering
KayakFit Workouts window listing saved sessions by filename with date and size, plus Choose file, Open folder, Summary, Save FIT and Upload actions

Your whole training history

Every session is saved and stays open to you. The Workouts screen lists them newest first — re-open any summary, re-export its FIT, re-upload to Strava, or reveal the raw files on disk. Nothing is locked away in a cloud account.

  • Browse & re-open every past session
  • Re-export FIT & re-upload any time
  • Plain CSV + FIT on disk — no lock-in

Built to stay out of your way

Lightweight, cross-platform and completely open — the essentials done right.

Real-time data

Every metric refreshed once a second while you paddle — no lag, no guesswork.

Session recording

Auto-pause, auto-laps and crash recovery capture every effort as CSV and FIT.

Performance analysis

Synced charts, per-lap splits and time-in-zone turn raw data into insight.

Clean interface

A calm, focused layout with light and dark themes that reads at a glance.

Cross-platform

One app, native on both macOS and Windows. No accounts, no cloud lock-in.

Open source & Python

Written in Python, MIT-friendly and fully auditable. Fast, lightweight, and yours to extend.

Open source

Built in the open, in Python

KayakFit is free and open source. The code is written in Python and fully auditable — no telemetry, no accounts, no paywalls. Contributions, issues and feature requests are always welcome.

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  • ✓
    MIT-friendly & freeUse it, fork it, ship it — no strings attached.
  • ✓
    Python poweredReadable, hackable and easy to contribute to.
  • ✓
    Privacy firstYour data stays on your machine. Strava is opt-in.
  • ✓
    Community drivenIssues and feature requests are genuinely appreciated.

macOS

Universal build for Apple silicon and Intel Macs.

Windows

Standalone build — no Python install required.

Ready to improve your kayak ergometer training?

KayakFit is free and open source for macOS and Windows. Grab the code, build it, and turn every session into data you can act on.

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