MuJoCo
Hacker ApprovedRanked 3 of 7 physics engines by recommenders
Free physics simulator that people recommend for robotics work, including browser use and JAX support. Critics note that simulated results can fail on real robotic hardware.
Free physics simulator that people recommend for robotics work, including browser use and JAX support. Critics note that simulated results can fail on real robotic hardware.
10 people gave an opinion
- recommend it
- 10
- criticize it
- 0
- approval share
- 100%
Recommended in 6 of 13 months
- November 2025: not recommended
- December 2025: not recommended
- January 2026: not recommended
- February 2026: recommended
- March 2026: recommended
- April 2026: recommended
- May 2026: recommended
- June 2026: not recommended
- July 2026: recommended
- August 2026: recommended
- September 2026: not recommended
- October 2026: not recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 10 people recommend itNeeds 10 or more, met.
- Nobody criticizes itNeeds 2 to 1 or better, met.
- Recommended in 6 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Frequently suggested for robotics simulation
“MuJoCo is great. I have it running in the browser for robotics simulation.”
Comment from 22 Apr 2026 in “MuJoCo – Advanced Physics Simulation” “The best one currently is MuJoCo.”
Comment from 4 Jul 2026 in “Drone Physics” “look into MuJoCo or OpenAI Gym”
Comment from 14 Feb 2026 in “Ask HN: How to get started with robotics as a hobbyist?” Runs in browser and with JAX
“MuJoCo is great. I have it running in the browser for robotics simulation.”
Comment from 22 Apr 2026 in “MuJoCo – Advanced Physics Simulation” “MuJoCo has a JAX backend so it should be fairly straightforward.”
Comment from 22 Apr 2026 in “MuJoCo – Advanced Physics Simulation”
What people warn about
Each mark is one comment
Simulations often fail on real hardware
“"visually stunning" simulations from engines like Isaac Sim, MuJoCo, or world models like Marble often fail the moment they are deployed on real robotic hardware”
Comment from 5 Mar 2026 in “SIPA: Auditing Physical Integrity in World Models and Robotics(Isaac SIM,Marble)”
Other physics engines people recommend
The four most recommended other physics engines, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| Box3D | 14 | 0 | 100% | 1 | — | — |
| Box2D | 12 | 1 | 92% | 1 | — | — |
| MuJoCoThis page | 10 | 0 | 100% | 6 | — | Approved |
| Jolt Physics | 9 | 2 | 82% | 5 | — | — |
| Rapier physics engine | 6 | 0 | 100% | 4 | — | — |
What people said
8 of the 10 comments that mention it, newest first. Each links to the original comment.
“The best one currently is MuJoCo.”
“MuJoCo has a JAX backend so it should be fairly straightforward.”
“MuJoCo is great. I have it running in the browser for robotics simulation.”
“This makes me so happy and excited!”
“The best thing is that we do not need to fight with NVIDIA software”
“it's basically because I don't have 20 years”
“"visually stunning" simulations from engines like Isaac Sim, MuJoCo, or world models like Marble often fail the moment they are deployed on real robotic hardware”
“look into MuJoCo or OpenAI Gym”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.