head to head · open source
hydra vs openGym
hydra has 17,627 GitHub stars, 1,615 forks, 98 open issues and last shipped 3 months ago. openGym has 15,277 stars, 2,008 forks, 109 open issues and last shipped yesterday. hydra leads on adoption by 15% (17,627 vs 15,277 stars). hydra is written in Go under Apache-2.0; openGym is written in JavaScript under AGPL-3.0. hydra has attracted 9% as many forks as stars, openGym 13%. openGym was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (docker), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| hydra | openGym | |
|---|---|---|
| GitHub stars | ★ 18K | ★ 15K |
| License | Apache-2.0 | AGPL-3.0 |
| Written in | Go | JavaScript |
| Last push | 2026-07-29 | 2026-10-24 |
| Forks | ⑂ 1.6K | ⑂ 2.0K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick hydra if
- You weight community size — 18K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Go
- You value the larger contributor base for long-term maintenance
pick openGym if
- You want the openGym feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches JavaScript
- You evaluated both and openGym fits your workflow better
About hydra
Chat · Discussions · Newsletter · Docs · Try Ory Network · Jobs Ory Hydra is a hardened, OpenID Certified OAuth 2.0 Server and OpenID Connect Provider optimized for low latency, high throughput, and low resource consumption. It connects to your existing identity provider through a login and consent app, giving you absolute control over the user interface and experience. What is Ory Hydra? Why Ory Hydra OAuth2 and OpenID Connect: Open Standards OpenID Connect Certified Deployment options Use Ory Hydra on the Ory Network Self host Ory Hydra Quickstart Who is using Ory Hydra Ecosystem Ory Kratos: Identity and User…
read the full hydra overview →
About openGym
A self hosted gym & body weight tracker you actually own. Plan your week, run guided workouts, track every set and your body weight over time — on your phone, synced across devices, behind your own passkey login. No account on someone else's server, no subscription, no ads. Just docker compose up . Home — today's workout & weight Guided workout — animated demos & sets Stats — heatmap, charts & PRs 🌐 opengym.duarte santos.ch · 📦 Source on GitHub · 🦊 GitLab mirror Screenshots, docs and the APK download live on the site. Want to poke at it first? The in browser demo is the real app with example data — no…
read the full openGym overview →
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Frequently asked questions
Is hydra or openGym more popular?
hydra has 17,627 GitHub stars and openGym has 15,277. hydra has the larger community by that measure.
Are hydra and openGym free?
Both are open source. hydra is licensed under Apache-2.0 and openGym under AGPL-3.0. Neither carries a licence fee.
What is the difference between hydra and openGym?
hydra is written in Go and openGym in JavaScript. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, hydra or openGym?
Choose hydra if you want the larger community (17,627 stars) or its Apache-2.0 licence terms. Choose openGym if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.