JustInterval.app is a passion project born out of necessity and a love for technology. My goal is to create a product that people can use freely, offering a high-quality alternative to expensive monthly subscriptions like Zwift or Rouvy.
I have been riding bikes since I was 8 years old (born in 1992). Living in Norway, where snow and harsh conditions often dominate the outdoors, indoor training isn't just an option—it's a necessity.
This tool started as a simple way to structure intervals for a spinning class I was instructing. However, it quickly evolved. I realized the potential to connect my Tacx Smart Trainer and Heart Rate strap directly to the browser, allowing me (and now you) to perform structured ERG mode workouts at home without complex software installations.
I believe fitness technology should be accessible. That is why JustInterval is free to use. There is a small ad on the start page to help cover hosting costs, but once you start your workout, the interface is completely distraction-free.
The development of this app is a continuous learning journey. It is built using a mix of modern web standards, my own hand-coding, and what I call "Vibe Coding" (AI-assisted development). This approach allows me to rapidly iterate and add functionality that users actually want.
My name is Magne Lima. By day, I work as a Technology Consultant at EY, where I am fascinated by the opportunities technology creates for businesses and people. By night, I am a cyclist and a developer.
I am always open to suggestions, code contributions, or funding discussions to help take this platform to the next level. If you have an idea or just want to say hi, please use the Feedback button on the main page to send me an email.
I wish you great health and fitness with the use of this app!