Run Pacer
Real-time voice pace coaching · iOS
PM + Product Design · In development · 2024
Existing running apps treat pace as data to display. I wanted something which treats pace as guidance to deliver. The difference is the interaction model.
Why I built this
I signed up for my first 5K with one goal: finish under 30 minutes. Simple math — 6:00 min/km. But when you're actually running, you have no intuitive sense of whether you're at 5:45 or 6:15. You're breathing hard, your legs are burning, and checking your pace means breaking form to dig out your phone or glance at your wrist.
I ended up in a loop: run, anxiously check, slow down too much, check again, speed up, check again. Instead of running I was monitoring. So I am designing the product I need. An app that just tells me in my ear whether to speed up, slow down, or keep going. Just a voice that says “perfect pace” and lets me focus on the run.
The design principle
Every design decision flows from one principle: the runner should never need to look at their phone. Most running apps are designed screen-first and add audio as an afterthought. Run Pacer inverts the model entirely.
The interaction model that shapes every product decision.
The 4-screen experience
The entire app is four screens. That's a deliberate product choice. Every screen that doesn't need to exist is a screen that can't confuse anyone.
Screen 1 — Goal setup
Screen 2 — Running view
Screen 3 — Run summary
Screen 4 — Run history
Five decisions that shaped it
Every feature I excluded — social, maps, heart rate, training plans, Watch app — is something others include. Saying no to them is what makes Run Pacer stand out.
Audio-first, screen-second
Voice and haptic feedback are the primary interface. The screen exists only for pre-run setup and post-run review. During the run, the phone goes in an armband and the screen becomes a backup.
Simpler product. More focused experience.
One question at setup: distance + time
No pace zones, no training modes, no threshold configuration. Just: 'I want to run 5K in 28 minutes. Go.' The app calculates required pace automatically. Target: 30 seconds from app open to running.
Less flexible. Far faster to start.
Adaptive feedback frequency
Running perfectly? You hear 'perfect pace' every kilometre. Drifting to 6:20? The app speaks up at 500m intervals. Way off-pace? Every 250m. The feedback frequency adapts to how well you\'re doing, so you get more guidance when you need it and less when you don\'t.
Better UX.
Music integration via audio ducking
Forcing runners to choose between pace guidance and their playlist is a dealbreaker. Run Pacer ducks music volume when delivering a cue, then restores it. Compatible with Spotify, Apple Music, and podcast apps.
Platform dependency. Non-negotiable for adoption.
Privacy by default — no account required
All data stored locally. No account needed for core features. GPS data never transmitted. Apple Health sync is optional. Many beginners don't want their pace data public or tied to an account. Run Pacer respects that.
More user trust.
How it competes
Strava is a social network that happens to track runs. Nike Run Club is a brand experience that happens to include coaching. Runkeeper is a GPS tracker that happens to have audio. None of them are built from the ground up around one job: help me hit my target finish time through real-time voice guidance.
Evaluated on one key metric: real-time adaptive pace guidance.
What's next
The MVP solves one problem completely. Four phases build from there:
Phone-free running. Pace guidance on the wrist with haptic patterns. Unlocks the "no phone at all" segment.
Pace zone analysis, improvement trends, monthly summaries, data export. For runners who've graduated from "finish my first 5K" to "shave 2 minutes off my PR."
Progressive pace programs, race-specific prep (5K, 10K, half marathon), adaptive rest days. This moves Run Pacer from a run-by-run tool to a training companion.
If social features ever come, they'll be opt-in and private by default.