Built to design your training — and keep it alive.
AI generates the plan; a real engine keeps it on track when life gets messy; deterministic rules keep it safe — and your data stays on your phone the whole time. Here's how it all fits together.
Talk to it in plain language
No long forms. Describe your goal — or how you're feeling today — and the coach builds your Season in 7-day blocks: the first is ready in seconds, the next quietly prepared before you reach it (so it works offline too).
On-device dashboard
Per-exercise toggles, rest timers, and nutrition all work with zero signal in a basement gym. Everything is stored right on your device — no server round-trip, no waiting to sync.
Forgiveness engine
Sessions, not calendar dates. Miss one and skip or do it later; miss many and pick up where you left off; miss a week and ease back in.
Deterministic safety layer
Every AI response is clamped or rejected by rule-based guardrails — calorie floors, protein bounds, volume caps, contraindication filters — before it's ever shown.
Best-in-class rest timers
Glanceable Roboto Mono numerals, ±15s quick-adjust, auto-advance, and a local notification the moment your rest ends — even with the screen locked.
Private progress photos
Weekly front/side photos compressed on-device to WebP and kept on your phone — never uploaded to any server. Your before/after stays yours.
Coaching that never hits a cliff.
AI Body Builder is continuous coaching delivered in 60-session Seasons — not a one-off program. Around session 50 we help you plan the next one: a goal transition like Hypertrophy → Strength, or a deload/peak cycle.
Your history, streaks, and photos persist across Seasons, so every chapter builds on the last.
- Skeleton + rolling blocks keep the plan personalized and always a step ahead.
- Goal transitions auto-generated by the same engine when a Season ends.
- Completion is a moment — a shareable, on-brand artifact you actually want to post.
- S1 Season 1 — Build60 sessions tuned to your goal, equipment, and schedule.
- 50 Plan your next SeasonTransition goals or run a deload — one tap.
- S2 Season 2 — ContinueHistory and photos carry over. No day-61 drop-off.
The part every other app gets wrong.
A busy week shouldn't cost you your streak. Session N unlocks when N-1 is done or skipped, so the plan waits instead of leaving gaps. Make-ups are capped at one workout per day — never two heavy sessions stacked.
- Missed 1 day: do it today or skip — the sequence advances cleanly.
- Missed 2–6 days: no shame, pick up where you left off, zero data lost.
- Missed 7+ days: ease back in, resume, or restart fresh — your call.
- Adherence % & session streaks reward showing up, not perfection.
- 1d Missed yesterday“Do it today, or skip it?” — one tap, no guilt.
- 2–6d Life got busyThe plan shifts forward automatically.
- 7d+ Welcome backLighter re-entry sessions to rebuild momentum.
Deterministic rules that a disclaimer can't replace.
A PAR-Q and a disclaimer are necessary but not sufficient — an LLM can hallucinate unsafe values. So a rule-based layer runs on every generated plan before it's saved or displayed, clamping or rejecting anything out of bounds.
- Nutrition floors & bounds: safe minimum calories and protein per your profile.
- Deficit cap: targets never more than ~20–25% below your estimated needs.
- Volume & intensity sanity: capped sets, no impossible loads, real rest days.
- Contraindication filter: joint, cardiac, and pregnancy flags reshape the plan.
- Clamp or rejectOut-of-range values are fixed or the block is regenerated.
- Health-screen awareYour PAR-Q answers feed the contraindication filter.
- Reasonable careAuditable rules, not “the AI said so.”
Coaching that doesn't harvest you.
Your profile, plans, logs, progress photos, and coach conversations are stored on your device — not on our servers. The app ships no ads, no analytics SDKs, and no third-party trackers, and we never sell your data.
Sign-in exists only to unlock the AI and apply your subscription. When you ask the coach something, the message needed to answer is sent to our AI provider to generate your response, then discarded — never stored by us and never used for ads.
- On-device by default: your fitness data lives on your phone.
- Photos never uploaded: compressed and kept locally, always.
- Zero trackers: no ad or analytics SDKs bundled in the app.
- Nothing to sell: we can't monetize data we never collect.
- Stored on your devicePlans, logs, photos, and chats stay local.
- No ads or analyticsNo trackers, no behavioral profiling.
- You stay in controlDelete the app and your data is gone.
Feature questions
See it work in your first session.
Your first 7 days are free — full onboarding and days 1–7, no credit card.