Our Story
Pace It was built by Dionysis Kastellanis, a runner and iOS developer based in Cyprus. He was training for a half marathon with an Apple Watch Ultra 2, putting in months of consistent work and had no way to tell whether any of it was making him faster.
The gap
Every running app showed what happened on a single run. Pace, distance, heart rate, splits. But none connected that data across months to answer a simple question: is the same effort producing faster pace over time? That trend is the clearest signal of whether training is working. It was not available anywhere.
At the same time, the Apple Watch hardware had reached the point where the sensors rival dedicated running watches. Cadence, stride length, ground contact time, running power. The native Workout app surfaces all of it, but the experience is still built for general fitness. There was nothing on watchOS designed exclusively for runners, with the kind of customization and structure that serious training requires.
As an iOS developer, he was in a position to build both: an analytics layer that connects months of training data and an Apple Watch workout app designed specifically for runners.
Reddit and early users
The first version was shared on Reddit, in running and Apple Watch communities. The response was immediate. Hundreds of runners said the same thing: they had been looking for exactly this. Threads turned into a feedback loop, a subreddit grew around the app and the first paying users were Reddit runners who had followed the build from the start.
That community shaped the product. Feature requests, bug reports, training use cases. Pace It was not designed in isolation. It was built alongside the runners who use it.
What it does
The analytics layer tracks pace in each heart rate zone month by month, surfaces the Training Load Ratio, derives personalized training paces from the last 60 days of running and rolls it all into the Pace It Index, a single 0 to 100 fitness score that reacts to real changes in training.
The Apple Watch app is a running-exclusive watchOS experience with 40+ metrics across 5 fully customizable screens, structured workouts with interval execution and a dashboard that syncs with the iPhone analytics. It was built to be the running watch app that the platform was missing.
Who it is for
Pace It is for runners who train with intent. Runners who know what heart rate zones are, who care about whether their zone 2 pace is getting faster and who want to know if their training load is in a productive range. It is not a tracker and it is not a coach. It is the layer in between: the one that connects months of data and tells you whether the work is paying off.
Privacy and pricing
All analytics are computed on the device. When integrations like Strava are connected, activity data passes through the server only to deliver it to the phone. No personal information is stored on servers. The app syncs with Strava, so any device or platform that connects to Strava can feed data into Pace It.
Pace It is free to download with a generous free tier. Deeper analytics and the Apple Watch workout app are available through a subscription, with a 7-day free trial and a lifetime purchase option.
Pace It is an independent, self-funded product.
Frequently asked questions
What is Pace It?
Pace It is an iOS and Apple Watch running analytics app. It tracks pace at heart rate over months, surfaces your Training Load Ratio, derives personalized training paces from your own data and rolls it all into the Pace It Index, a single 0 to 100 fitness score.
Who built Pace It?
Pace It was built by Dionysis Kastellanis, a runner and iOS developer based in Cyprus. He trains with an Apple Watch Ultra 2 and built the app because no existing tool could show whether his training was producing results over time.
How is Pace It different from Strava or Garmin?
Strava tracks individual runs and adds a social layer. Garmin shows what happened during a session. Pace It connects months of data and shows whether the same heart rate is producing faster pace over time. It answers a different question: not what happened on a single run, but whether training is actually working.
Does Pace It work with Strava?
Yes. Pace It syncs with Strava, so any device or platform that connects to Strava can feed data into Pace It. You do not need to change how you record your runs.
Is Pace It free?
Pace It is free to download with a generous free tier. Deeper analytics and the Apple Watch workout app are available through a subscription, with a 7-day free trial and a lifetime purchase option.
Does Pace It store my data?
All analytics are computed on your device. When you connect integrations like Strava, activity data passes through the server only to deliver it to your phone. No personal information is stored on servers.
Who is Pace It for?
Pace It is designed for runners who train with intent. Runners who know what heart rate zones are, care about whether their easy pace is improving and want their data to show them something useful rather than just logging another run.
For questions, ideas, or to talk about running, reach out at support@paceit.app or join the community on Reddit.