# MuJoCo

10 Hacker News commenters recommended MuJoCo and 0 criticized it, November 2025 to November 2026. It was recommended in 6 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** 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.

## Why people recommend it

- Frequently suggested for robotics simulation (3 comments): "MuJoCo is great. I have it running in the browser for robotics simulation." ([source](https://news.ycombinator.com/item?id=47862513)) "The best one currently is MuJoCo." ([source](https://news.ycombinator.com/item?id=48788940)) "look into MuJoCo or OpenAI Gym" ([source](https://news.ycombinator.com/item?id=47016458))
- Runs in browser and with JAX (2 comments): "MuJoCo is great. I have it running in the browser for robotics simulation." ([source](https://news.ycombinator.com/item?id=47862513)) "MuJoCo has a JAX backend so it should be fairly straightforward." ([source](https://news.ycombinator.com/item?id=47866114))

## What people warn about

- Simulations often fail on real hardware (1 comments): ""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" ([source](https://news.ycombinator.com/item?id=47267614))

## Alternatives hackers recommend

- [Box3D](https://hackerapproved.com/p/box3d.md): 14 recommend
- [Box2D](https://hackerapproved.com/p/box2d.md): 12 recommend
- [Jolt Physics](https://hackerapproved.com/p/jolt-physics.md): 9 recommend
- [Rapier physics engine](https://hackerapproved.com/p/rapier.md): 6 recommend
- [BepuPhysics 2](https://hackerapproved.com/p/bepu-physics.md): 6 recommend

## Cite as

Hacker Approved, "MuJoCo", https://hackerapproved.com/p/mujoco/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).