New app

New app: grynd.wtf

grynd.wtf launched on 13 Feb 2026: Free browser app for structured workouts on a 3D track or a YouTube video, with no account and your rides kept in the browser.

Innovation: text, images, YouTube clips and your webcam placed on a workout's timeline, shown as the ride reaches them

Visit grynd.wtfAll about grynd.wtf

An ERG workout in grynd.wtf ridden on a road video: 69 W target and actual, heart rate, cadence, speed and distance, the workout profile and zones on the right, with the V2W badge on and the 3D track in a small window.
Marco Meßer · grynd.wtf
grynd.wtf riding a route on its 3D track, coloured by gradient with the upcoming grades marked, beside heart rate, cadence, the route's elevation profile and time in zones, with virtual gear 12 at the bottom.
Marco Meßer · grynd.wtf
The grynd.wtf workout editor: a 60-minute threshold workout of warm-up, two 20-minute steady blocks at 219 W and a cool-down, with FTP, weight, templates and FTP tests in the sidebar.
Marco Meßer · grynd.wtf
A completed Sweet Spot workout in grynd.wtf opened from the calendar: the interval chart and ride time, with average power, NP, IF, TSS, work and cadence.
Marco Meßer · grynd.wtf

4 screenshots. Scroll or swipe sideways.

About grynd.wtf

grynd.wtf is a web app for building, riding, planning and analysing indoor workouts, a spare-time project by Marco Meßer that is in testing. The editor builds workouts from warm-up, steady, interval, ramp and cool-down segments, generates new sessions from templates from Recovery to Sprint, and includes four FTP tests. Workouts run in ERG mode on any Bluetooth FTMS smart trainer, on a 3D track, alongside a YouTube video in picture-in-picture, or on a YouTube video whose playback speed follows your power. GPX routes ride with gradient simulation on a 3D track that climbs and descends with the route, and free rides have 24-gear virtual shifting. A calendar plans workouts, and an analysis tab shows each ride with normalized power, IF and TSS. Imports .zwo, .fit, .gpx and .tcx files and CSV ride data; rides export as .fit, workouts as .zwo and the plan as .ics. Bluetooth heart-rate monitors connect too, and Bluetooth controllers can be mapped to actions in the ride. There is no account: workouts, calendar and rides stay in the browser's storage, and a shared workout link carries the workout after the # sign, which never reaches the server; the site counts visits with Umami, without cookies. Runs in Chrome, Edge, Opera, Brave and Arc on Windows, macOS, Linux, ChromeOS and Android, not on iPhone or iPad, and can be installed as a PWA. In German and English. Free; you can support it through Buy Me a Coffee.

Features

  • ERG mode
  • Workouts
  • Routes
  • Video
  • Virtual shifting
  • Own routes

Sends rides to

  • Any tracker, by file (FIT, TCX…)

All news

App details

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