Hi, I’m Donghyun.

Frez started with questions I kept asking during training. Is today a strong day, or am I below my usual level? Should I keep going at this intensity? How your body feels matters, but it was hard to compare today with last week by feel alone. A thermometer gives you a number for body temperature. I wanted a number that could help me make sense of strength and training intensity in the same practical way.

I did not set out to build a brand or a piece of hardware. I connected an easy-to-find force sensor to a phone and put its signal on screen as a number.

The app was rough, but I posted it on r/climbharder so other people could try it. Back then it was called ClimbHarder. As I listened to the people using it, I learned that measuring the same way over time was more useful than chasing one peak result. I added the features people needed one by one, and ClimbHarder became Frez. The name comes from ‘freeze,’ a nod to the way the body stays still while producing force during isometric training. I shortened the word to Frez.

The first post is still here if you would like to read it. ↗

I understood the value of this kind of measurement only after trying it myself. But when the equipment costs hundreds of dollars, it is hard to ask someone who has never used it to take that chance. If the price stops you before you begin, you never get to find out whether it is useful to you.

So I kept the hardware purchase separate from the app’s paid features. I wanted Dyno’s price to keep that first measurement within reach. Basic measurement and isometric training in the app are free; people who want more can choose Pro. Pro revenue keeps Frez running and pays for new features and support.

Frez began as a small app. Thanks to the people who used it and chose Pro, I was able to develop and produce Frez Dyno. What started as an app became a physical measuring device. I will keep refining both the app and Dyno so more people can measure their strength easily and turn those results into training.