# browserengineering/book

Web browser engineering (a book)

Repository: https://github.com/browserengineering/book
Canonical: https://ross.abutalabs.com/products/browserengineering-book
Homepage: https://browser.engineering/
Language: JavaScript
License: MIT
License Family: permissive
Last push: 2026-08-15T15:43:48+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 35, longevity 100
- inputs: {"age_days": 2877, "days_push": 18, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1159, forks 105 (observed 2026-08-28T04:03:48.672469+00:00)

## What it is
The source for 'Web Browser Engineering', an open-access book by Pavel Panchekha and Chris Harrelson that teaches how web browsers work by building a basic but complete browser in Python. The repository contains the Markdown book text, a build pipeline to HTML, and chapter-by-chapter browser implementations (lab1.py through labN.py) plus unit tests.

## Use cases
- learn how web browsers work internally
- build a simple browser from scratch in Python
- understand HTTP, HTML parsing, and CSS layout fundamentals
- study browser rendering, compositing, and scheduling
- use a textbook for a browser engineering course
- understand how JavaScript execution and the DOM work in a browser
- learn about browser security concepts like cookies, XSS, and CSRF

## When to choose
- you want a hands-on, code-driven explanation of browser internals
- you are teaching or self-studying web browser engineering
- you want to incrementally build a working browser chapter by chapter
- you prefer free, open-access educational material with runnable code

## When to avoid
- you need production-grade browser code or a real browser engine
- you want a reference manual for a specific browser like Chrome or Firefox
- you are looking for web development tutorials rather than browser internals
- you need a JavaScript-based browser implementation (the labs are in Python)

## Facets
- artifact type: learning-resource
- maturity: active
- function: documentation, interpreter, parser, graphics
- domain: web-development, tutorials, education, developer-tools
- platform: python, cross-platform
- tags: book, browser-engineering, rendering, html-parsing, css-layout, javascript-engine, networking, open-textbook, web-server

## Member repositories
- browserengineering/book (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:48.672469+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:31:52.721954+00:00, confidence not recorded.
  - readme: https://github.com/browserengineering/book (fetched 2026-08-28T04:03:48.672469+00:00, sha 30554383909e)
  - homepage: https://browser.engineering/ (fetched 2026-08-29T12:36:48.476266+00:00, sha 9765445e9df9)
  - site_page: https://browser.engineering/about.html (fetched 2026-08-29T12:36:48.485582+00:00, sha 82cc99de74cf)
- Data as of 2026-08-30T08:39:29.467469+00:00.