Why

Most workout apps lock your data behind a login on their servers, nag you to upgrade, or disappear when the startup does. openGym is the opposite: it runs on your box, your data stays in a folder you control, and it's yours to fork. It still feels modern — installable as a home-screen app, passkey sign-in, offline support, sync across your phone and laptop.

Features

• ⚖️ Body-weight tracking — interactive chart with a goal line you set, gains/losses colored by whether they move toward it
• 🏋️ Weekly plan — a routine per weekday, over a library of 1,324 exercises (searchable, with animated demos), browsable by muscle on a body map
• ✨ Four starter plans — Push/Pull/Legs, Upper/Lower, Full Body, 5×5; loaded as ordinary routines you can edit, and a routine can be copied in one tap
• 🗓️ Reschedule any day — sick, missed a session, or fewer gym days this week? Move a workout to another day without touching your weekly plan
• 📅 Your week starts where you say — Monday or Sunday, in Settings. The weekly plan, the day strip on Home, the calendar and every "this week" total follow it, so the app reads the way the calendar on your wall does
• 🧭 A workout screen that gets out of the way — one ⋯ menu per exercise (note, details, progression, bar weight, warm-up, superset, swap, move, remove), the set number as the set's own menu (drop set, rest-pause burst, remove), and a scrollable list view of the whole session with the header pinned. Four switches under Settings → Workout controls bring any of the old button rows back
• 🌈 Colour-coded RIR / RPE — one tap logs how hard a set was, with a sentence per level ("one more rep in the tank"); the same colour whether you think in RIR or RPE, a free field for in-between values
• 📖 History without leaving the workout — the exercise's last sessions and a progress line, from the ⋯ menu or the exercise details
• ⭐ Favourite exercises — star what you use, it sorts first in the picker and the library
• ▶️ Guided workouts — it knows what day it is and starts today's session; asks your body weight first, pre-fills your weights from last time, rest timer, PR detection, per-exercise weight tracking. On a rest day it doesn't just say "rest day" — it names when your next session is and what it is
• 🙈 Animations are your call — the exercise demos can be full size, small, or hidden entirely during a workout. Hidden collapses the media rather than leaving a gap, for anyone who finds a looping GIF between sets more distracting than useful
• ☀️ The screen stays awake while you train — no unlocking the phone and finding your place again between every set. On for as long as a workout is running, released the moment you finish it, and switchable off in Settings
• 🔗 Supersets — plan them into a routine or pair two exercises mid-session with “make superset with previous/next”, then work through the group back-to-back with a single rest at the end of each round. Unpair at any time; a group of one dissolves itself
• 🔥 Warm-up sets — mark the ramp-up rows as warm-ups and they stay out of the numbers that should not see them: no effect on your estimated 1RM, your progression, or the fatigue map, while still being there in the session where you need them. A weight change cascades down the rows that share their phase, not across the divide
• ➖ Change your mind mid-session — add an exercise you decided to do, or remove one you didn't, without ending the workout. Removing a member of a superset asks which one
• ⏱️ Timed exercises — planks, hangs, wall sits and loaded carries are logged by time, not reps, with a work timer that counts the set itself (separate from the rest timer) and logs the time you actually held. They can carry weight too
• ⏲️ Rest per exercise — heavy triples and curls don't want the same break: give any exercise its own rest time and it overrides the global timer for that exercise (a superset rests once, taking the longest). Travels with shared plans
• 🧘 Planned deloads — flag a routine as excluded from automatic progression: its sessions open with the routine's own target weights, stay in your history and statistics, and never become the baseline your next regular session progresses from
• 📈 Progression that follows a rule — pick one per routine, override it per exercise: linear, Greyskull LP (AMRAP top set, double jumps, 10 % resets), double progression through a visible rep range (both bounds editable, per-side exercises step in twos), or adding time. Your weights are already right when the session opens, and every target says why it's that number. Missed reps never advance the load, stalls trigger a deload, and bodyweight exercises progress in reps instead
• 💪 Estimated 1RM — per exercise, from your best eligible set (it names which one), with its own progress curve and a calculator for sets you haven't done. Won't guess above 12 reps
• 🎯 Effort per set, in your scale — an optional third column rating how hard a set was, as RIR (reps left in the tank) or RPE (the same judgement on a 10-point scale). Off by default; each set keeps the scale it was logged with, and nothing else reads the value — your progression and 1RM are unaffected
• 💪 Bodyweight exercises, logged as bodyweight — push-ups, pull-ups, dips and 300-odd others arrive knowing they carry no load, so there's no weight column and no working-weight prompt: one stepper, log the reps. Add a dip belt and it reads as an addition, and progression goes back to following the weight. Without one, reps climb — and past a ceiling you set, a set is added instead of a rep, up to the point where the honest advice is load or a harder variation
• ↔️ Reps per side — for lunges, single-arm rows and the rest. You log the total, the app shows the split ("8 per side"), and the target steps in twos so it never lands on a number one side can't have
• 🏋️ Plate math for barbell work — barbell, EZ, trap bar and Smith machine carry a bar weight (20 kg / 45 lb and friends, or your own per exercise), and the workout screen tells you what goes on each side: Bar 20 kg · 30 kg per side. You still log the total, so your history, progression and 1RM keep meaning exactly what they always did
• 📝 Log a past workout — forgot your phone, trained on paper, or switched apps? Add a session after the fact from History: date, start time, duration, routine or freestyle, then the normal workout screen — weights, reps, RIR/RPE, timed sets and all. If that day already has a workout you choose: replace it, keep both, or cancel. Backfilled sessions never claim PRs against workouts that came later
• 🎲 Freestyle sessions — train without a plan and pick exercises as you go. Each one arrives prefilled from the last time you did it — same sets, same reps and weight by position — so an unplanned session doesn't start by asking you to retype last week
• 🏃 Cardio — log time + speed, not just weight × reps
• 📤 Share a plan — send someone your routines and week schedule as a small file (no workouts, no weigh-ins), or print it as a clean PDF. Importing merges, so their plan is never overwritten
• 🔧 Filter by equipment — narrow the library to what you actually own; the options adapt to what you've picked, so every combination on screen has results behind it
• ✨ Your own exercises — a name and a body part is enough; they behave like built-in ones everywhere, with an optional description instead of an animation
• 🟩 Activity heatmap — a GitHub-style year view, shaded by time spent training
• 💪 Muscle map, three ways — a front-and-back body diagram you can read as Balance (where the volume went, over a week, a month or all time — naming the muscles you haven't trained), Fatigue (what is still recovering, weighted by how close each set was to your maximum, decaying smoothly rather than expiring at a window edge) or Strength (how long since you trained each muscle, and behind every one the exercises that built it with their estimated 1RM). It previews what a routine hits while you build it, and shows what you just trained when you finish. Male or female figure, your pick
• 📳 See the timer end, not just hear it — an opt-in screen flash when a rest or work timer finishes, for loud gyms and headphones
• 🔔 Push notifications — rest-timer alerts even with the app closed, plus an optional reminder on days you have a workout planned but haven't logged one — on the Android app scheduled per calendar date, so a day you already trained or rescheduled stays quiet. Opt in per profile; keys are generated on first run, nothing to configure
• 🔑 Passkeys, not passwords — Face ID / Touch ID / fingerprint login; each profile keeps its own data, synced across devices. Sign-ins last 90 days by default (configurable), and “sign out everywhere” in Settings ends every session on every device at once
• 🛠️ Admin dashboard (optional) — for whoever runs the instance: who's training right now, per-user history, disable accounts, invite-only signup, and an activity log of sign-ins, failed attempts and admin actions. Off by default, so a fresh instance stays open with no admin
• 🎨 Designed, not assembled — light/dark themes and 8 accent colors saved to your profile, over a hand-drawn icon set instead of emoji, so it looks the same on every phone
• 🌍 14 languages — full UI translation (EN, DE, ES, FR, IT, PT (Portugal), PT (Brazil), PL, TR, RU, ZH, KO, HI, TH, HU); exercise instructions localized in 12 of them and built-in exercise names shown bilingually in PT-BR and HU, all loaded on demand so the app stays fast
• 📥 Bring your history with you — import from FitNotes (Android and iOS), Strong and Hevy (CSV or directly with a Hevy Pro API key), or body weight straight out of an Apple Health export. Exercise names are matched against the library and anything unrecognised becomes one of your own exercises, so nothing in the file is dropped
• 📦 Yours to keep — one-tap JSON export/import, guest mode, no telemetry; switching kg ↔ lb offers to convert every stored number
• 🤖 Ask an AI about your training (optional) — an MCP server lets a client like Claude Desktop or Cursor read your history in your own words: "what did I bench last week?". Read-only, spawned locally by the client, nothing leaves your box. Not in the Docker build — if you don't use an AI assistant, it isn't there
• 🧠 An AI coach that writes your plan (optional, off by default) — answer a handful of questions and it designs a week of routines; later it reads what you actually logged and proposes changes, each one with the evidence behind it. You approve every change and can undo it. It runs on your server under your provider account — Anthropic, OpenAI, Gemini or any OpenAI-compatible endpoint (Ollama on your LAN counts) with a pasted API key on the default image, or the Claude Agent SDK / Codex CLI on a separate build. The phone app can use your instance or its own key. See docs/AI_COACH.md
• 📱 Standalone Android app — the whole tracker as a sideloadable APK: no account, no server, data on the phone, native workout reminders, and an in-app update check that downloads the next signed APK and verifies its checksum (download)

Quick start (self-host)

You need Docker with Compose.

git clone https://github.com/DuarteSantos8/openGym
cd openGym
cp .env.example .env
docker compose pull   # grab prebuilt images (amd64 + arm64) — skip to build from source instead
docker compose up -d

Open http://localhost:8080, tap Create profile, and you're in. First launch downloads the exercise media (~140 MB) once.

About that media: it reaches openGym through hasaneyldrm/exercises-dataset, which redistributes ExerciseDB v1 — its metadata and instruction text are MIT, but the images and animations are third-party content under neither that MIT license nor openGym's AGPL, and their ownership is currently disputed between Gym visual and ExerciseDB. openGym ships none of it: your instance downloads it from upstream. Reusing it yourself, commercially or not, means clearing it with the rights holder — see NOTICE.md. The prebuilt images are published twice, from the same tag: registry.gitlab.com/duartesantos8/opengym/{api,web} (what docker-compose.yml pulls) and ghcr.io/duartesantos8/opengym-{api,web} on GitHub — swap the image: lines if you prefer GHCR. Prefer building the images yourself instead of pulling from a registry? Drop the pull step and run docker compose up -d --build — you don't need Node or a build step locally either way.

Want it reachable from your phone over the internet with passkeys? You'll need an HTTPS domain — a two-line change in .env. See docs/SELF_HOSTING.md.

Mobile app (no server at all)

The same codebase also builds a standalone mobile app (Capacitor): no account, no sync, no backend — everything stays on the phone, with native workout-day reminders and share-sheet backups. Self-hosting gets you multi-device sync and profiles for friends & family; the mobile app is the install-and-done flavor.

• Android: download the APK — or straight from GitLab's package registry or the GitHub release, where every build sits next to its .sha256 — and sideload it; openGym is deliberately not on the Play Store. Or build it yourself: docs/MOBILE.md.
• iPhone: Apple doesn't allow installing apps outside the App Store, so there is no iOS download. Self-host and add it to your home screen from Safari (it's a full PWA), or build the native app onto your own device from Xcode — see docs/MOBILE.md.

How it works

┌─────────────┐        ┌──────────────────────────────┐
│  Your phone │──HTTPS─▶│  web  (nginx)                │
│  / laptop   │        │   ├─ serves the built app    │
└─────────────┘        │   └─ proxies /api ──────────┐│
                       └──────────────────────────────┘│
                                                        ▼
                                        ┌──────────────────────────┐
                                        │  api  (Node + WebAuthn)  │
                                        │   └─ ./data (JSON files) │
                                        └──────────────────────────┘

• frontend/ — React + Vite (React Router + Zustand), built to static files inside Docker
• api/ — Node with no framework, two dependencies (@simplewebauthn/server for passkeys, web-push for notifications), storing everything as plain JSON files under ./data
• web/ — a multi-stage image that builds the frontend and serves it with nginx, proxying /api to the backend so it's all on one origin (passkeys require this)

The full HTTP API is documented as an OpenAPI spec in api/openapi.yaml — browsable at opengym.duarte-santos.ch/api.html.

Your data

Lives in ./data on your host: db.json (profiles + public passkeys), state-<user>.json (each user's plan, workouts, body weight, settings), audit.log (the admin activity log — sign-ins and admin actions, no IP addresses unless you ask for them) and secret (the session-cookie key). Back up ./data and you've backed up everything. Passkey private keys never touch the server — they stay in your phone's secure hardware / your password manager.

Configuration

All via .env (see .env.example):

Push notification keys are generated on first run and saved to ./data/vapid.json — nothing to set. DATA_DIR is pinned to /data by docker-compose.yml and mapped to ./data on the host; change the host side of that volume, not the variable.

Roadmap

The plan lives in ROADMAP.md, and the GitHub milestones hold the issues. A release every two weeks, each one small and themed: the promised items, editing finished workouts, the session queue, programmes and phases, the progression engine, cardio — then v1.4.0, the foundation: storage moves to a database and search is rebuilt, the one compatibility break — then accounts (password and OIDC login, trainer role, MCP write), the iOS app, the Android and health items, and what all of that unlocks (pictures for custom exercises, catalogue work, skins, social). Ideas and pull requests welcome.

Tech

React 19 + Vite (React Router, Zustand) · Node (no framework) · nginx · Docker Compose · WebAuthn · exercise data from hasaneyldrm/exercises-dataset (MIT metadata and instructions; media © Gym visual — see License). No database server, no cloud dependencies — the frontend builds inside Docker, so self-hosting stays a one-command docker compose up.

The training logic — progression rules, 1RM estimation, how a logged session is read back — lives in pure functions under frontend/src/lib/ with tests next to them: npm test in frontend/. Vitest is a dev dependency; the app itself ships no runtime dependencies beyond React, the router and Zustand.

The optional AI Coach (api/coach/) is built the same way round: a by-name allowlist decides what may leave the server, and a closed-list validator decides what may come back — the model can touch routines and the weekly schedule, nothing else, and every change is applied on the client only after you approve it. The core of it — api/coach/core/ — has no Node dependency, so the phone app runs the same validator the server does. The in-container AI runtimes live in a separate Docker build target; the API-key providers need none. See docs/AI_COACH.md.

The same pure helpers power an optional MCP server (mcp/) that lets an LLM client like Claude Desktop read your data over stdio — see mcp/README.md. Opt-in, not in the Docker build.

Community

• Discord — release announcements, self-hosting help and the back-and-forth that would be a slow issue thread. Quickest way to get an answer.
• Issues — bugs, questions, self-hosting help and ideas. (Issues still open on the GitLab mirror are read too.) Label a question question and an idea idea, and it gets treated as one rather than as agreed-on work. Use an issue over the Discord for anything the next person should be able to find by searching.
• Login trouble? Most of it is an RP_ID/ORIGIN mismatch — check docs/SELF_HOSTING.md before opening an issue.
• Pull requests — see CONTRIBUTING.md. Merge requests already open on the GitLab mirror are still reviewed and land on main here; new work, please, as a pull request.

GitHub is home; GitLab is a mirror. github.com/DuarteSantos8/openGym was offline from 2026-08-19 to 2026-09-10 while the account was suspended, and the project lived on GitLab in the meantime. It is back, and gitlab.com/DuarteSantos8/opengym is now kept in sync by a GitHub Actions workflow on every push to main and every v* tag — nothing is pushed or merged there by hand. The mirror stays because its CI builds the release artefacts: the signed APK, the multi-arch images (GitLab registry, mirrored to GHCR) and the SBOMs. (gitea.com/DuarteSantos/openGym is a plain mirror.) In CHANGELOG.md, !NN is a GitLab merge request from those weeks; #NN refers to whichever tracker the report came through.

Contributing

Issues and PRs welcome — see CONTRIBUTING.md. Good first issues: more starter plans, exercise-data languages, import from other trackers. A ⭐ helps more people find it.

openGym is free and stays free: AGPL, no subscription, no paid tier, nothing held back for sponsors. If it replaced a paid tracker for you and you want to chip in, there's a coffee button below (and a badge at the top) — a star, a bug report or a merge request is worth just as much.

License

openGym's own code is GNU AGPL v3.0 — free and open source. You can self-host, use, modify and share it; if you run a modified version as a network service, you must offer that version's source under the same license. Nobody can turn openGym into a closed, proprietary product.

Third-party content is not, and openGym cannot sublicense it. The exercise metadata and instruction text originate from ExerciseDB v1 and reach openGym through hasaneyldrm/exercises-dataset under the MIT license. The exercise images and animations are third-party content covered by neither that license nor the AGPL, and their ownership is currently unresolved — the upstream dataset attributes them to Gym visual under a non-transferable permission, while ExerciseDB/AscendAPI claims to be their creator and owner. A clarification has been requested. openGym does not redistribute them (your instance fetches them at first run) and does not relicense them. To reuse that media yourself, clear it with the rights holder first.

Full third-party notices, including the body-diagram geometry: NOTICE.md.