A Swiss apprentice's workout log gets 20,000 stars in 111 days: how openGym got pushed up

A Swiss programmer still in apprenticeship built a fitness-tracking web app with Claude Code, open-sourced it in July, and by Nov 6 it had 19,907 stars and 2,657 forks on GitHub. No Hacker News, no paid promotion. The stars came from three evenings: a few X accounts that specialize in pushing GitHub projects each posted about it. This piece breaks down why it got picked up, how far the stars are from real users, and which steps to copy if you want a project to earn stars the same way.

"Is this useful to anyone else?"

Duarte Santos is doing a four-year apprenticeship in app development at Sunrise, a Swiss telecom company. In early summer 2026 he wanted something simple: to log sets, track his bodyweight, and see whether he was getting stronger at the gym. On the "About" page of the project site he wrote that every app he tried "either wanted a subscription, or an account, or put my training data on someone else's server, usually all three". So he did what people who mess around with home servers often do: he wrote a mobile web page, hosted it on his own server, and used it himself.

In July 18 he open-sourced the code under AGPL, then posted to r/coolgithubprojects on Reddit under the title:

I built a self-hosted, open-source gym tracker — is this useful to anyone else?

As of July 31, the repo had 214 stars (GitHub, 7-31).

What it is

A free, open-source, self-hostable strength training log app. The web version can be installed to a phone's home screen, and docker compose up runs it on your own machine with one command. There's also an iPhone + Apple Watch version (10-23, free, listed on the App Store), and the Android version is shipped as an APK on GitHub.

In features it doesn't feel like an "open-source alternative" so much as a commercial app. 5,600 It has many animated exercises, shows which muscles you're working on a body diagram, automatically adjusts weight according to rules, calculates plate loading, has a rest timer between sets, supports about twenty languages, and can import your history from Strong, Hevy, and FitNotes in one click. The AI coach is optional and off by default. To use it, you enter your own model key.

The first screen of the README says: no account on someone else's server, no subscription, no ads, no telemetry.

How the stars came: three posts

Each jump lines up with a specific post. After 10-04, it stayed on the JavaScript Trending chart for almost a month (from 10-04 to 11-01 it was in the top 25 nearly every day, per trendshift). The chart then kept bringing in traffic on its own, and sites like daily.dev, opensourcealternatives.to, and selfhostedworld picked it up. By 11-06, it had gained 2,393 more in the last 7 days, with a single-day peak of 384.

Apart from the recommendation accounts, the author kept posting milestones to Reddit himself: r/selfhosted ("now on the App Store"), r/SideProject and r/buildinpublic ("9 stars in 900 weeks"), r/foss ("1000 stars, thanks from the person who built it"), and r/coolgithubprojects ("15000 stars, your donations paid for every developer account"). These posts didn't draw much, but they gave the repo a few hundred stars and a respectable front before the recommendation accounts ever came by. On TikTok, two reposted videos each got about 100k views (@github.signals 8-21, @whitewhoadie 10-21), titled "A GYM TRACKER YOU ACTUALLY OWN".

Why this project got picked

It can be explained in one line. "Free, no subscription, no account, your data is yours, more features than the paid apps". Reposts in English, Spanish, and Chinese almost all repeat only this line. Users of Hevy, Strong, and Fitbod already resent subscriptions, so the line gets shared as soon as someone says it.

It actually works. Open-source fitness logging already existed: wger has been around for 2013 years with 7.2k stars, but its interface is dated. workout-cool has 8.7k stars and leans toward a coaching and scheduling website. openGym was the first to combine a modern interface, self-hosting, native phone and watch apps, and one-click import from rival apps. Recommendation accounts pick projects by whether the first screen of the README looks like something you can install right away: hero image, badges, a live demo, App Store and APK buttons. It has all of them.

The ban became the story. The ban on 8-24 was bad news, but ErickSky framed it as "banned for giving away something good", and that became the post that travelled furthest. You can't copy this one, and you shouldn't try.

The repo stayed active. The author says on the About page that most of the code, tests, and docs were first drafted by Claude Code, and that he handles the trade-offs, the review, and testing on his own phone. The result: one apprentice, working alone, shipped roughly 35 releases from 7-21 to 11-03, and 9-11 saw several in a single day. Release notes credit community PRs ("twenty merged pull requests from ten contributors"), and the Discord has 2,095 members (11-06). A visitor who lands on it from Trending sees a repo that was updated yesterday.

Stars are not users

Behind 20,000 stars, real usage is much smaller. The iPhone version has 28 ratings in the US store (4.89 stars, App Store, 11-06). Release attachments on GitHub have about 120k cumulative downloads, mostly APKs, including repeat downloads on each update. Self-hosted instances have no telemetry, so the user count is invisible from outside. Before 10-31 the China store had only 1 ratings, and 11-06 was 10, which lines up with the wave of Chinese reposts.

So these stars mostly represent developers voting that "this is a good story", not twenty thousand people using it at the gym. For anyone trying to collect stars, that's actually good news: the audience you need to win over is developers scrolling X, not gym-goers.

Money: none. It's free under AGPL, with only Buy Me a Coffee and Ko-fi tips, enough to cover developer account fees. The third-party host ElfHosted sells managed hosting of openGym, but that is their business, not the project's.

Who's following

Most of the 2,657 forks are probably just one-click deployments (an inference, I didn't check them one by one). The visible followers are all small: nathanmarinas2 reskinned it as "LiftNex" (0 stars); alexpcosta/opengym is a mirror from the ban period (1,001 stars); Mocas-12/gym-gym is a Chinese-language, fully local fitness PWA (11 stars; I didn't verify whether it was inspired by this project). The fitness-logging niche is already held by this project, so a second open-source fitness app won't get picked up by the recommendation accounts again.

If it were you

Verdict: This playbook is worth copying, but don't copy the category. Pick another app that "everyone pays a subscription for and feels reluctant about", and build a polished, free, open-source alternative whose README opens with "No subscription, no account, no ads". There's only one real bet: whether a recommendation account picks you up.

Good fit for: independent developers who can build the full frontend and mobile app, who are heavy users of the category themselves, who can keep a weekly release cadence with tools like Claude Code or Cursor, and who are willing to spend months building slowly on Reddit and X.

Bad fit for: people who want to make money from an open-source project (this category basically earns nothing, at most tips and other people selling hosting); people who only want a web demo (recommendation accounts pick projects that are polished enough to install and replace a paid app on your phone); people who want to build another fitness logger (that slot is full).

How to do it:

• Choosing a category: apps with large paying user bases, very private data, and clear feature boundaries, such as bookkeeping, period tracking, habit check-ins, meditation timers, vocabulary flashcards, and photo backup. Start by searching GitHub for "self-hosted <category>" and check whether existing open-source projects have dated interfaces or lack a good mobile version.
• Build the importer in version one: one click to import the CSV export from the rival app, so switching costs nothing. openGym's Strong/Hevy import is the point that keeps coming up in the reposts.
• One-command deployment, a live demo you can try in the browser, and a mobile version (a PWA first, then the App Store once there's traction).
• Treat the README as a landing page: hero image, badges, screenshots, and store buttons on the first screen.

How to get users: Post in r/selfhosted, r/SideProject and r/coolgithubprojects with "I built X, is it useful to anyone?" Then post at each milestone (100, 500, 1000 stars, App Store launch). Once you have a few hundred stars and a decent front page, @ or DM the X accounts that push GitHub projects (English accounts like Tom Dörr, Spanish ones like ErickSky). After you hit Trending, ship a release every week and thank community contributors by name in the notes, so the repo stays alive the weeks it's on the charts. Chinese and Spanish repost accounts will pick it up on their own.

How long you have: No hard deadline. But the "open-source alternative + AI-written code" story is still fresh, and the more time passes, the more similar projects the recommendation accounts will see. Aim to ship a version you can use daily as a replacement within 3 months.

Signs you're reading it wrong: ① Your project has been out for 2 months, you've posted on Reddit three or four times, and it still hasn't passed 300 stars. That means you picked the wrong niche, or the first screen doesn't explain it. ② A recommendation account reposts you and the same day you don't gain 500. That means it's not finished enough: people look, don't star. ③ openGym's daily star gain drops to a few dozen or fewer before the end of 2026, while no new "open-source alternative" project reaches the top of Trending over the same period. That means the wave is over.

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Data and sources: stars and forks come from GitHub (11-06). Daily growth and Trending rank come from trendshift.io (repositories/88268). X post views and likes were checked after posting; dates are in the body. The iPhone rating comes from the App Store (11-06). The Discord member count comes from the Discord invite page (11-06). The author's background comes from his GitHub profile and LinkedIn. The About page and release history come from opengym.ch. For Reddit posts we only got titles; scores and exact dates were not verified.