Matter.js 2D Physics Engine

Matter.js is a JavaScript 2D physics engine for the web, providing rigid body physics simulation with collision detection, constraint solving, and compositing for games and interactive applications. Created by Liam Brummitt in 2014, the project has over 16,000 stars as of 2026 and is one of the most popular JavaScript physics engines. Key features include: rigid body dynamics (full 2D rigid body simulation with position, velocity, angle, angular velocity, mass, inertia, and friction for bodies of arbitrary shape), collision detection (broad phase using grid-based spatial partitioning and narrow phase using SAT (Separating Axis Theorem) for convex shapes, plus efficient collision pairs management), body shapes (circle, rectangle, polygon, trapezoid, and compound bodies created from multiple parts with vertices and chamfering), constraints and joints (distance, spring, pivot, mouse, and compound constraints for connecting bodies with configurable stiffness, damping, and length), sleeping bodies (bodies that come to rest are put to sleep to save computation, waking on collision or force application), gravity and forces (configurable world gravity, per-body force application, and custom force fields), events (collision start, collision active, collision end, before update, after update, and sleep start/end events for game logic integration), rendering (built-in wireframe renderer, plus Matter.Render for textured rendering and Matter.RenderPixi for WebGL rendering), mouse constraint (interactive mouse-based body dragging for user interaction), composite world (managing collections of bodies, constraints, and composites with add, remove, and clear operations), plugins (MatterAttractors for gravitational attraction, MatterGravityWell, MatterWrap for world boundary wrapping, and MatterEvents), and modular API (Engine, World, Bodies, Body, Composite, Constraint, Events, Mouse, Render, and Runner modules with composable design).