ADAPTIVE HEALTH ENGINE

Your plan
re‑solves
every morning

Most apps hand you a 12-week program and hope you keep up. FitLex reads last night’s dinner, your sleep, your HRV and yesterday’s soreness, then rebuilds today’s session before you wake up — and tells you exactly why it changed.

Start 7 days free
No card for the trial
Android & iOS · India and worldwide
Plan solver runs on-device Full offline gym mode
K
Tuesday, 26 August Good morning
18
79 READY
TODAY’S SESSION Upper — push 52 min · 6 exercises
Volume trimmed 12%
Start workout
Energy balance 830 left
3%

of health & fitness app users are still active on day 30

3–4×

churn rate for anyone under three workouts in their first fortnight

Day 14

is the whole game. FitLex is built around getting you three sessions in before it — by removing every reason to skip one.

WHAT NOBODY ELSE DOES

Four things that
only work together

Every one of these exists because a specific thing makes people quit. Fix the reason, keep the user.

Closed-loop plan solver

Apps track your food or train you. None re-solve tomorrow’s session from last night’s dinner, your sleep, HRV and soreness as one optimisation. Volume, load and rest all move together.

Recipe Memory

Photo calorie AI tops out at 75–85% on Indian home food, because every household’s rajma is different. Log your recipe once and FitLex matches it forever — no classifier, no guessing.

Form Twin

Every form checker compares you to a generic ideal. FitLex compares this rep to your own best rep — which is the only way to catch fatigue-driven breakdown before it becomes an injury.

Auto-aligned time-lapse

You shoot in random poses and lighting, so normal progress reels look jerky and unconvincing. FitLex pose-normalises and light-normalises every shot, so twelve weeks plays back as one smooth change.

HOW THE ENGINE WORKS

The AI never sets your weights

Handing everything to a language model is expensive, non-deterministic and unsafe — it will happily prescribe a 100 kg squat to a beginner. So we split the job in two.

LAYER 1 Dart + TypeScript · zero cost · offline

Deterministic solver

Volume landmarks per muscle (MEV / MAV / MRV) Double progression with RPE autoregulation Readiness from sleep, HRV, strain and soreness Injury × equipment × time-available filter
Emits a set of safe options and load ranges — nothing else.
LAYER 2 Language model · cached · budget-guarded

Chooses and explains

Picks among solver-approved options for variety Writes the human explanation for today Parses “20 min hai, kandha dukh raha hai” Generates variations inside the safe envelope
It can never set a load, rep count or volume directly.
PRICING

Free forever keeps you training

The daily plan and workout logging never expire. Paid tiers add the parts that need a camera, a wearable or a lot of compute.

Core

Free
Forever, no card
Daily adaptive plan Workout logging, offline Food search & barcode
Download
MOST PEOPLE PICK THIS

Plus

₹399/mo
Billed yearly · 7 days free
Everything in Core Form Twin & Recipe Memory Body time-lapse Unlimited coach & wearable merge
Start 7 days free

Pro

₹899/mo
Billed yearly
Everything in Plus Live voice coach in-session AI-generated exercise video Priority human review
Start 7 days free

Three sessions.
Fourteen days.

That is the only thing standing between you and actually sticking with this. FitLex is built to get you there — then it keeps re-solving for as long as you keep showing up.

Start 7 days free No card needed for the trial