FitSI service description
This page is the reference description of FitSI for people, reviewers, search engines and AI assistants. It separates what is being built for the first pilot from what is planned later. FitSI has no public release yet.
| Product | AI training coach in Telegram (chat + Mini App) |
|---|---|
| Stage | In development; closed pilot by invitation |
| Training types in v1 | Strength (bodyweight, bands, dumbbells, kettlebells, gym), running, cardio, intervals (Tabata format), warm-up, stretching, mobility |
| Platforms | Any device with Telegram: Android, iOS, desktop, web |
| Languages | Site: English, Russian and Polish |
| Public API | None |
Interfaces
Coach name and tone
You give the coach a name and pick a tone: calm, strict or friendly. The name is used in chat and reminders. Load rules, restriction checks and safety do not depend on the name or tone.
Coach chat in Telegram
Onboarding, questions, plans, reports and reminders happen in a Telegram chat.
Telegram Mini App
Profile, equipment and the week plan come first; workout cards and the interval timer follow, more screens later.
Planning
Profile
Goal, experience, available days, current level and any injuries or limits in your own words. You can fill it in parts.
Goal to week plan
Goal, starting level, stages, week plan, individual sessions, results and adjustment. Several goals can share one week with priorities.
Session structure
Each workout has a purpose, warm-up, blocks, dosage, rest, intensity guidance, substitutions, instructions, stop conditions and a cool-down or stretch.
Warm-up, stretching and mobility
The warm-up is matched to the main part of the session. Stretching and mobility close a session or run as short standalone sessions that count as light days.
VO2 max training
For a VO2 max goal the plan includes long intervals, such as 4 × 4 min at high intensity with active recovery, and easy sessions in between. Progress is judged by workouts and, with a connected watch, by its VO2 max estimate. The estimate is the device’s own calculation, not a lab test.
Template library
Plans are adapted from a versioned library of templates rather than invented from scratch in chat.
Automatic adjustments
FitSI may lighten or move a day’s session and explains why. Changing the goal or rebuilding the program requires your confirmation.
Daily guidance
Morning check-in
Short questions about sleep, fatigue, pain and readiness when no device data is available.
Reminders and quiet hours
Reminders before sessions and in the evening; each type can be switched off. After two days without a reply FitSI sends one check-in and then waits.
Weekly review
Completed sessions, goal progress, obstacles and plan changes.
Workouts and reports
Ad-hoc workouts
“20 minutes, a band and a mat” produces a session that counts toward the week. By default it replaces the planned session; an extra session needs your explicit choice.
Interval timer
Work and rest intervals in the Mini App: card, timer, report, review.
Reports
Text, a screenshot of a watch summary, or an API record. Extracted values are shown for correction; unknown fields stay unknown.
Exercise technique illustrations
Reviewed materials first. Generated images are labelled and are not treated as verified instruction.
Voice input
Possible extension after the text version.
Equipment
Equipment profiles
Home, gym, country house or a temporary travel kit.
From a photo
Recognition returns candidates with uncertainty. Weight and load-bearing safety are never inferred from appearance.
Gym video
After the photo version.
What FitSI remembers, and what it won’t assume
A coach is only useful if it remembers the right things. FitSI stores them as facts you can see and correct.
Restrictions stay in force
If your knee limits jumping, “let’s go harder” does not cancel that. Changing a restriction is a separate question: what changed and since when.
Today’s level, not old records
A 10 km race from three years ago is stored with its date. Plans start from your recent training.
No data is not “recovered”
Without sleep data or a check-in, the plan stays visible with a note that today’s state is unknown, and the load is not raised.
Photos are suggestions
A photo can show dumbbells or a band, but not their weight, the band’s resistance or whether a bar is safe to hang from. You confirm them.
Device integrations
API access is confirmed only with real responses from the provider. Until then, manual reports and screenshots are the supported path.
| Garmin | Checking access | Official Garmin Connect Developer Program access is granted after an application review. Not available yet. The Health API documents sleep with stages and score, overnight HRV, resting heart rate, stress, Body Battery, respiration, Pulse Ox, VO2 max and activities. Training Readiness was not found in the official API documentation. |
|---|---|---|
| Polar | Checking access | Testing which sessions are available via Polar AccessLink. AccessLink documents exercises with Training Load Pro, continuous heart rate, cardio load, Sleep Plus Stages and Nightly Recharge with overnight HRV. Polar H10 is not used as a sleep source. |
| Apple Health | Planned later | Requires a native iOS app; after the pilot. Planned data: sleep, HRV, resting heart rate, VO2 max and workouts. |
| Health Connect (Android) | Planned later | Requires a native Android app; after the pilot. Planned data: sleep stages, HRV, resting heart rate and exercise sessions. |
| Manual input and screenshots | Building for pilot | Supported path for the first pilot. |
Data and AI boundaries
- Training and profile data are stored in FitSI’s own PostgreSQL database; each user’s data is isolated.
- Messages pass through Telegram and the selected AI model provider. Only the context needed for a request is sent to the model, not your full history.
- The application validates every AI proposal (structure, exercises, equipment, dosage and active restrictions) before it is saved or shown.
- The AI coach has no access to arbitrary database queries, shell commands or secrets.
- Health data are not sent to group chats. Logs do not contain tokens, test results, images or full chat text by default.
- Export and deletion of personal data and disconnection of integrations will be available before the pilot is extended beyond the first users.
What FitSI does not do
- Diagnose conditions or prescribe treatment, including from lab results.
- Override a stored health restriction because you ask for a harder workout.
- Treat missing sleep or device data as a sign of good recovery.
- Guess the weight of equipment or the safety of household objects from a photo.
- Plan nutrition or diets in the first version.
- Give instant access after a waitlist request.
FitSI, a workout app or a personal trainer?
| FitSI (planned) | Typical workout app | Personal trainer | |
|---|---|---|---|
| Where you talk to it | Telegram chat and Mini App | Its own app | In person or messenger |
| When it is available | Any time, answers right away | App always, but no dialogue | By appointment, usually 1–3 times a week |
| Remembers goal, limits and gear | Yes, as dated facts you can see | Partly, in settings | Yes, while they remember |
| Name and tone | Your choice | No | Their own |
| Rebuilds the week after a missed day | Yes, with a reason | Often fixed programs | Yes |
| Strength, cardio and stretching in one plan | Yes, as one weekly load | Usually one focus | Depends on the coach |
| Works without a smartwatch | Yes, short check-ins | Varies | Yes |
| Checks your technique live | No | Some apps, by camera | Yes |
FitSI does not replace a doctor or an in-person coach. For rehabilitation or competition coaching, work with a professional.
Who the pilot is for
A good fit if you
- want to train regularly without deciding what to do each day
- want strength, cardio and stretching in one plan
- train with what you have: a band, dumbbells, a park or a gym
- are an adult and use Telegram every day
Not a good fit if you
- need a supervised rehab plan after an injury
- need diagnosis or medical advice
- prepare for competitions with a fixed program
- are under 18