SimArena

Browser-based simulation, data collection, and training for robotics.

SimArena is where robotics teams build robot models, design test environments, collect training data, and set up training runs — all in the browser, without installing ROS, MuJoCo, CAD software, or anything else. It fixes the most painful part of robotics development: the time spent on setup before real experiments can even begin.

Build Robot → Design Scene → Run Sim → Collect Data → Train

Who It’s For

Robotics teams that need fast iteration on sim environments. Researchers collecting demonstration data for imitation learning. Developers building agents that need a simulated test environment. AI agents that need to design or validate robots on their own.

URDF Builder

Browser-based robot editor:

Define links, joints, meshes, collision shapes, and mass properties
Import from several formats (URDF, CAD, others)
Export to URDF, MuJoCo XML, Isaac Sim formats
Visual debugging of meshes and joint structure
AI assistant for edits and automatic adjustments
Solves the CAD-to-URDF problem entirely in the browser

Builder [Alpha Version]

Scene Editor

Drag-and-drop editor for test scenes:

Place and configure assets (objects, furniture, fixtures)
Add scriptable behavior in Python — hooks for on_episode_start, on_episode_end, pre_step, post_step
Scripts can randomize positions, define success/failure conditions, write to a .output context the training algorithm reads
Agent mode: chat to make scenes, generate 3D assets from photos or videos, import Gaussian splat scans of real spaces
Code editor runs Python directly in the browser
Export scenes and logic to MuJoCo, Isaac Sim, Genesis, or other simulators

Physics engines: MuJoCo WASM (in-browser), Rapier, PhysX — or route to Fabric cloud for Isaac Sim, MuJoCo, or Genesis on GPU.

Editor [Alpha Version]

Simulation Execution

In-browser — MuJoCo WASM, Rapier, or PhysX for light work
Cloud via Fabric — Isaac Sim, Genesis, Newton, or full MuJoCo on GPU. Results stream back to the browser.

Data Collection & Training

Load any scene from the editor and record demonstration episodes
Export datasets in LeRobot format or other standard formats
Send datasets to CodecFlow for training. Configure RL or imitation learning recipes.
Community feature in scoping: list scenes on a marketplace where other users collect data and earn rewards from the creator

Capture [Alpha Version]

How We Charge

Credits system — top up for agent mode, asset generation, cloud sim time, training
Tiers — free and paid plans ($59/month Builder, $149/month Team — each includes monthly credits; pay-as-you-go credits on top)
API / MCP server — agents can design robots or build test scenes on their own. Pay per use with x402.

	Free	Builder	Team	Enterprise
Price	$0 + credits	$59 + credits	$149 + credits	Custom
Free credits/month	500 (~$5)	3,000 (~$30)	10,000 (~$100)	Custom
Active projects	1	5	Unlimited	Unlimited
Environments	5	50	200	Unlimited
Storage	2GB	10GB	100GB	Custom
Cloud sim concurrency	1	5	20	Custom
In-browser physics	✅	✅	✅	✅
Cloud sim (Fabric)	❌	✅ (pay Credits)	✅ standard rates	✅ custom rates
Team workspaces & roles	❌	❌	✅	✅
API / MCP access	Limited	✅	✅ higher limits	✅ custom
Support	Community	Email	Priority	Dedicated
SSO / audit logs	❌	❌	❌	✅
SLA	❌	❌	❌	✅

Status

Beta released. v1 launching soon. Used by 6 robotics teams in alpha.