URDF Validator — check a URDF file online, no ROS install
Free online URDF validator: checks XML structure, link/joint integrity, kinematic tree, inertia sanity, and joint limits directly in your browser. Nothing is uploaded.
What this validator checks
| Check | Why it matters |
|---|---|
XML well-formedness & <robot> root | First failure point for every URDF parser |
| Link/joint referential integrity | Joints referencing undefined links fail at load time in ROS |
| Single-tree structure (one root, no cycles) | URDF cannot represent kinematic loops — a common migration error from SDF |
| Mass > 0 and inertia triangle inequality | Gazebo silently drops zero-mass links; invalid inertia destabilizes physics |
| Joint limits on revolute/prismatic joints | Required by spec; parsers disagree on missing defaults |
Explicit joint axes, package:// mesh URIs | The classic sources of "works in RViz, breaks in Gazebo/Isaac" |
Why URDF files break between tools
URDF parsers in RViz, Gazebo, Isaac Sim, MuJoCo importers, and PyBullet disagree on defaults: missing joint axes fall back to (1,0,0) in some parsers and error in others; zero-mass links load in RViz but are silently dropped by Gazebo; package:// mesh URIs resolve only inside a ROS workspace. Validating structure before switching tools catches most of these divergences early.
Need to validate whole robot description packages, batch-check CI pipelines, or convert CAD to URDF? See the Pro tools →