This is a collection of information and links intended to be useful to developers of ECMAScript engines and tooling. Pull requests are most welcome! :^)

Logo	Name	Website	Source code	Implementation Language	License	Supported ES version
	BESEN		https://github.com/BeRo1985/besen	Object Pascal	LGPL-2.1	ES5
	Boa	https://boajs.dev	https://github.com/boa-dev/boa	Rust	MIT
	ChakraCore		https://github.com/chakra-core/ChakraCore	C++	MIT
	Duktape		https://github.com/svaarala/duktape	C	MIT	ES5.1, ES6/7 (partial)
	Elk		https://github.com/cesanta/elk	C	AGPL-3	subset of ES6
	engine262	https://engine262.js.org	https://github.com/engine262/engine262	JavaScript	MIT	ESNext
	Escargot		https://github.com/Samsung/escargot	C++	LGPL-2.1	ES2020
	Flathead		https://github.com/ndreynolds/flathead	C	MIT
	goja		https://github.com/dop251/goja	Go	MIT	ES5.1
	GraalJS (GraalVM JavaScript)	https://www.graalvm.org/dev/reference-manual/js/	https://github.com/oracle/graaljs	Java	UPL-1.0	ESNext
	Hermes		https://github.com/facebook/hermes	C++	MIT	ES6 with some exceptions
	Higgs		https://github.com/higgsjs/Higgs	D
	iv		https://github.com/constellation/iv	C++	BSD-2-Clause	ES5.1
	JavaScriptCore	https://trac.webkit.org/wiki/JavaScriptCore	https://github.com/WebKit/WebKit/tree/main/Source/JavaScriptCore	C++, JavaScript	LGPL-2.1	ESNext
	JerryScript	https://jerryscript.net	https://github.com/jerryscript-project/jerryscript	C	Apache-2.0	ES5.1
	Jint		https://github.com/sebastienros/jint	C#	BSD-2-Clause	ESNext
	JS-Interpreter		https://github.com/NeilFraser/JS-Interpreter	JavaScript	Apache-2.0
	Kiesel	https://kiesel.dev	https://codeberg.org/kiesel-js/kiesel	Zig	MIT
	LibJS	https://libjs.dev	https://github.com/SerenityOS/serenity/tree/master/Userland/Libraries/LibJS	C++	BSD-2-Clause	ESNext
	mJS	https://mongoose-os.com	https://github.com/cesanta/mjs	C	GPL-2	subset of ES6
	MuJS	https://mujs.com	https://git.ghostscript.com/?p=mujs.git	C	ISC	ES5
	Nashorn	https://openjdk.org/projects/nashorn	https://github.com/openjdk/nashorn	Java	GPL-2.0	subset of ES6
	njs	https://nginx.org/en/docs/njs/	https://hg.nginx.org/njs	C	BSD-2-Clause	ES5.1, ES6+ (partial)
	Nova		https://github.com/trynova/nova	Rust
	Otto		https://github.com/robertkrimen/otto	Go	MIT	ES5
	Porffor	https://porffor.goose.icu	https://github.com/CanadaHonk/porffor	JavaScript	MIT
	QtJsEngine/Qv4	https://doc.qt.io/qt-6/qjsengine.html	https://code.qt.io/cgit/qt/qtdeclarative.git/tree/src/qml	C++	LGPL
	QtScript	https://doc.qt.io/qt-5/qtscript-index.html	https://code.qt.io/cgit/qt/qtscript.git	C++	LGPL
	QuickJS	https://bellard.org/quickjs/	https://github.com/bellard/quickjs	C	MIT	ES2020
	Reeva		https://github.com/ReevaJS/reeva	Kotlin	BSD-2-Clause
	Rhino	https://mozilla.github.io/rhino	https://github.com/mozilla/rhino	Java	MPL-2.0	subset of ES6
	Spidermonkey	https://spidermonkey.dev	https://searchfox.org/mozilla-central/source/js	C++, Rust, JavaScript	MPL-2.0	ESNext
	Starlight	https://teletype.in/@starlight-js	https://github.com/Starlight-JS/starlight	Rust	MPL-2.0
	tiny-js		https://github.com/gfwilliams/tiny-js	C++	MIT
	V8	https://v8.dev	https://source.chromium.org/chromium/chromium/src/+/main:v8/	C++, JavaScript	BSD	ESNext
	XS (Moddable SDK)	https://www.moddable.com	https://github.com/Moddable-OpenSource/moddable	C	LGPL-3	ES2021

Note ESNext indicates that the engine generally targets the latest ECMAScript standard without major exceptions.

• esvu - esvu is your one-stop shop for all implementations of ECMAScript
• jsvu - JavaScript (engine) Version Updater

• eshost - A uniform wrapper around a multitude of ECMAScript hosts
• eshost-cli - Run ECMAScript code uniformly across any ECMAScript host

• ECMA-262 - ECMAScript Language Specification
• ECMA-402 - ECMAScript Internationalization API Specification

• test262 - Official ECMAScript Conformance Test Suite
• LibJS tests - Tests developed for LibJS with a Jest-like framework

• test262.fyi - Daily runner of test262 for many engines
• test262.report - test262 results for various engines (defunct as of 2022-09)
• boajs.dev/boa/test262 - test262 results for Boa
• libjs.dev/test262 - test262 results for LibJS (AST, bytecode, parser tests)

• bterlson/test262-harness - Experimental harness for test262, uses eshost
• linusg/libjs-test262 - test262 runner for LibJS
• LibJS test-js - Custom test runner for the LibJS tests

TODO: Babel, Sucrase, SWC

• ECMAScript proposals
• TC39 - Ecma TC39 committee standardizing ECMAScript
• WinterCG - Web-interoperable Runtimes Community Group