Two Apple Watch apps. Two very different ideas about what running should feel like.

WorkOutDoors is one of the most configurable Apple Watch running apps out there. That's also its biggest problem. Before you've even started a run, you're managing GPX files, building interval sessions from scratch, and configuring data screens. Confusing terminology, confusing menus, and so many settings that mistakes are basically part of the deal. It's powerful, sure. It's also exhausting.

Our co-founders Jan and Tobi were exactly the kind of runners who appreciated what WorkOutDoors could do. They wanted the data, the structure, the training depth. What they couldn't stand was how much work it took just to get going. Not to mention how much room for error came with it.

Apple Watch has all the sensors you could ever need. It just needed an app that made everything simple.

So we built one. That's Milo.

Configuration isn't coaching

WorkOutDoors gives you tools. A lot of them. But it assumes you know how to use them, and more importantly, that you want to. You decide what workouts to run, what pacing targets to set, how to progress over time, and when to push or back off. For some runners, that level of control is exactly what they're after.

For most, it's just friction before the run has even started.

Milo is built around better decisions, not more options. Instead of asking you to build your own system, Milo provides one that adapts as you train. It answers the questions that actually matter: Am I building fitness or just accumulating fatigue? Is today right for intensity? Is my load progressing safely? What should I run next? You just run. Milo handles the rest.

Your training state, before you even head out

This is where Milo does something WorkOutDoors simply doesn't. Before you lace up, Milo builds a complete picture of where you're actually at today. Not just your recent runs, but everything that affects your readiness:

Your current training stress balance, so you know whether you're primed to perform or quietly digging a hole. Your sleep data and averages, because how you're sleeping changes everything about how you should train. Time since your most recent activity and your most recent run specifically, because the body doesn't just care about volume, it cares about rhythm. And more signals on top of that, all pulled together into a single, clear assessment.

Then it tells you what your body is ready for, whether that's a hard workout, an easy run, or a rest day. It'll even tell you the best time of day to run based on the weather.

That's your holistic training state. WorkOutDoors can show you data. It can't tell you what to do with it.

Routes that actually work

In WorkOutDoors, using a route means hunting down a GPX file, downloading it to your computer, figuring out how to get it onto your phone, then importing it through the file system. If you know what you're doing, it eventually works.

With Milo, you add a route on your phone or the web in seconds and it syncs to your watch automatically. That's it. No file management, no digging through folders, no fussing around. And when you're out there running it, you get a live view with real detail — not just a dot on a map.

See it in action: watch our import a route tutorial.

Workouts that are just as easy

Same story with workouts. In WorkOutDoors, building a structured workout means sitting down and configuring it from scratch. Intervals, targets, steps, all manual.

In Milo, you pick a structured workout or easily create your own in a couple of taps and you're running. Your training paces are already built in and they adapt automatically as your fitness changes, so every workout is calibrated to where you actually are right now, not where you were three months ago when you first set up the app. No guessing, no manually updating targets. Just the right intensity, every time.

See how it works: watch our create a workout tutorial.

WorkOutDoors knows your runs. Milo knows you.

WorkOutDoors records your workouts. That's it. It doesn't know anything else about you. No sleep data, no resting heart rate, no broader health context. Just the run you did.

Milo connects to HealthKit and pulls in the full picture. Your sleep, your recovery, your heart rate trends, all of it feeding into the analysis and your daily training state. It's a completely different level of insight, and WorkOutDoors simply can't match it.

And unlike apps that send your health data to the cloud, everything stays on your device. Nothing is sent to our servers. You still get full, immediate analysis of your training load, sleep, recovery, readiness, VO2 Max trends, and more, all computed locally on your phone.

The one thing to know: Milo does sync some things to our servers for cross-device use, specifically your routes, workouts, and activities recorded with the Milo app. But your HealthKit data never leaves your device.

Signal vs. density

WorkOutDoors tracks the basics for each run. Pace, heart rate, splits, elevation - the standard stuff. Milo tracks all of that too.

The difference is everything else.

Milo connects your runs and workouts into something bigger. Detailed training load charts showing how acute and chronic load are trending over time. A drill-down view so you can understand what was actually happening, not just see that something happened. Training stress balance that tells you whether you're primed to perform or quietly digging a hole. You're not just reviewing a workout. You're seeing how it fits into the block.

Sleep is woven into all of it. Milo tracks your averages and factors them into your readiness every single day — because fatigue isn't just about miles, it's about recovery.

And VO₂ Max isn't a number you glance at and move on. You can track how it's developed over time and compare it directly against your weight for a more honest read on your aerobic fitness trajectory. It's not just how much you ran. It's whether it's working.

How they compare

There's a lot more coming

We're just getting started. Deep run analysis, pace analysis, pace relative to temperature, pace relative to weight, and more are all in the works. The foundation Milo is built on as a running training app makes this kind of insight possible in a way that a configuration-first app like WorkOutDoors simply isn't designed for.

The goal has always been the same: give serious runners the depth they want, without making them work for it.

Built by runners, for runners

If you've used Workoutdoors and loved the depth but hated the complexity, that feeling is literally why Milo exists. We wanted everything it could give us without everything it asked of us. So we built that app. Simple, powerful, and actually delightful to use every day.