HIIT15Open App

How it works

Three steps. Zero decisions.

Designed for busy professionals: the fastest path from 'I have 15 minutes' to a sweat that actually counts.

01

Step 01

Open the app

No signup. Pick your difficulty. Today's 15-minute session is already queued.

02

Step 02

Prop your phone

Camera on. The AI sees your body and counts reps in real time — all on-device.

03

Step 03

Move, hit rest, repeat

Warm-up · HIIT rounds · Cool-down. Voice coach counts you in and calls form fixes.

AI coach · proven

Your phone becomes a
real form coach.

MediaPipe pose landmarks run on-device at 15 fps. It counts reps, checks joint angles, flags depth and tempo, and stops the set if a critical joint goes out of safe range. No video ever leaves your phone.

Live · on-device

Reps

14

Air squat · L2

Form

92%

Rep counting

Joint-angle state machine per movement archetype.

Form cues

Live voice: 'Deeper', 'Chest up', 'Slow the descent'.

Safety stop

Auto-pauses the set if knees, back or neck drift into risk.

100% on-device

Camera frames never touch a server. No account needed.

Workout library

One session a day.
Never the same.

A rotating program covering every movement pattern — push, pull, hinge, squat, core and cardio — with warm-up and cool-down included in every 15 minutes.

Fat-loss

Torch

12 min HIIT · full body

15 min · L1–L3→

Legs · Core

Strength

Bodyweight lower + core

15 min · L1–L3→

Upper

Push

Chest, shoulders, triceps

15 min · L1–L3→

Upper

Pull

Back + biceps · isometric

15 min · L1–L3→

Recovery

Mobility

Hips, T-spine, hamstrings

15 min · L1–L3→

Cardio

Sprint

Cardio finisher · 8 rounds

15 min · L1–L3→

App preview

Built for one hand,
a sweaty screen.

Large type, thumb-sized controls, no menus during the workout. Screen stays awake. Voice coach handles the rest.

Round 4 / 6 · Work

Squat jumps

Explode up · soft landing

28

seconds

14

reps

92%

form

Next

rest 10s

  • Wake-lock keeps the screen on the whole session
  • One-tap start · 3-2-1 audio countdown into every round
  • Auto-advance between warm-up, work, rest and cool-down
  • Adaptive difficulty — L1 to L3 with progressions per exercise
  • Installable PWA — feels like a native app, updates instantly

Stay committed

Habits beat motivation.
We optimize for habits.

HIITPrime is built on the behavioral mechanics that actually work — friction removed, streaks visible, decisions eliminated.

Streaks

Miss a day, the ring breaks. Simple, unforgiving, effective.

Same time daily

Optional gentle reminder at your chosen slot.

One decision

Today's session is already picked. Press start.

Under 15 minutes

The whole app is engineered against your excuses.

Why HIITPrime works

Science-backed.
Excuse-proof.

Time-efficient

Meta-analyses show short-interval HIIT delivers comparable VO₂max gains to sessions 3× longer.

Full-body

Every session covers push, pull, hinge, squat and core so nothing is neglected.

Progressive

L1 → L3 progressions per movement means the workout scales with you, not past you.

Behavior-designed

One decision, one CTA, one streak. Friction is engineered out.

The excuse-proof workout

15 minutes.
Starting now.

Start free — 14 days →See pricing

No card. No login. Works offline.

Start free — 14 days →