esfuzz is a command‑line and library tool that automatically generates random, syntactically‑valid ECMAScript programs (as SpiderMonkey‑compatible ASTs) and runs them through multiple JavaScript parsers (e.g., SpiderMonkey Reflect.parse, Acorn, Esprima, UglifyJS, ZeParser). It is aimed at language implementers and parser authors who need generative fuzz testing to uncover parsing bugs and ensure AST round‑trip fidelity.