SpiderMonkey is Mozilla's JavaScript engine written in C and C++. It is used in various Mozilla products, including Firefox, and is available under the MPL2.

Standalone source code releases can be found on the Releases page.

Guides

Building

SpiderMonkey Build Documentation
How to get SpiderMonkey source code, build it, and run the test suite.

Using SpiderMonkey

Introduction to the JavaScript shell
Documentation of the command-line JavaScript shell, js.
JSAPI User Guide
This guide provides an overview of SpiderMonkey and describes how you can embed engine calls in your applications to make them JavaScript-aware.
JSAPI cookbook
Shows the JSAPI translation of some commonly used JavaScript expressions and statements.
GC Rooting Guide
Guide on how to write code compatible with the Generational GC in SpiderMonkey.
How to embed the JavaScript engine
An older tutorial about embedding SpiderMonkey.

Hacking on SpiderMonkey

New to SpiderMonkey
A guide to hacking on SpiderMonkey.
Setting up CDT to work on SpiderMonkey
How to configure Eclipse to work on the SpiderMonkey code.
Running Automated JavaScript Tests
How to run the JavaScript test suites.
Creating JavaScript tests
How to add tests to the JavaScript test suites.

Reference

JSAPI Reference
SpiderMonkey API reference.
JS Debugger API Reference
API reference for the Debugger object introduced in SpiderMonkey 1.8.6, which corresponds to Gecko 8.0 (Firefox 8.0 / Thunderbird 8.0 / SeaMonkey 2.5).
Bytecode descriptions
Listing of SpiderMonkey's bytecodes.
Parser API
Reflection of the SpiderMonkey parser, made available as a JavaScript API.

Tips, tricks and philosophy

Future Directions
Future directions for functionality, design, and coding practices.
SpiderMonkey Internals
A design overview and a file-by-file walkthrough of the implementation.
Bytecode Reference
SpiderMonkey bytecode reference.
SpiderMonkey Internals: GC
Separate internals article on the GC
SpiderMonkey Internals: Hacking Tips
Collection of helpful tips & tools for hacking on the engine

Releases

SpiderMonkey release notes
Current and past versions: 52, 45, 38, 31, 24, 17

Community