Trotinho

Trotinho is a free interval timer that runs in the browser. You set work and rest intervals, choose how many repetitions to do, and get audio cues so you can switch between efforts without checking the clock. It offers three formats: intervals with work, rest and repeats; rounds with breaks between activity blocks; and a free timer that runs without a countdown and lets you choose when to be alerted.

The main use case is run-walk sessions, such as running for one minute and walking for ninety seconds, repeated eight times. The same timer also works for sprint intervals, HIIT and gym rounds. Trotinho is an interval timer rather than a GPS tracker, so it does not record routes or distance.

It is aimed at people who train on their own and want a simple way to keep time, and at people who want to build their own interval sessions. Workouts can be saved without creating an account, and they stay on the device, so a backup should be exported before changing phones. The site also mentions a planned paid version and a coaching area, both still in development.