marcelduran/yslow
YSlow analyzes web pages and suggests ways to improve their performance based on a set of rules for high performance web pages. observed · 2026-08-28
Health v2 · maintenance only
32/100
- Activity 0
- Release rhythm 35
- Longevity 100
Flags: no_releases
How is this computed?
round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10) — computed 2026-09-03. Adoption (stars, forks) is never an input.
- gap_med: n/a
- age_days: 5334
- days_rel: n/a
- days_push: 1293
- n_releases_24m: 0
Adoption not part of the score
2200 stars · 373 forks observed · 2026-08-28
What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded
YSlow analyzes web pages and grades their performance against Yahoo's rules for high performance web pages. It ships as browser extensions, a bookmarklet, and a Node.js/PhantomJS command-line tool that analyzes HAR files.
Use cases
- analyze web page performance against best-practice rules
- audit page load speed from HAR files on the command line
- find why my website loads slowly
- grade web pages for performance optimizations
- run headless web performance analysis in CI
- measure front-end performance of a web page
When to choose
- you want classic Yahoo performance-rule grading of web pages
- you need a CLI to analyze HAR files for performance issues
- you want a browser extension or bookmarklet for on-page performance audits
When to avoid
- you need modern Core Web Vitals metrics like LCP or CLS
- you want actively developed tooling - the project is largely in maintenance mode
- you need full Lighthouse-style audits including accessibility and SEO
Facets
cli-tool · maturity maintenance
analytics monitoring http-client browser-extension web-development performance developer-tools frontend browser cli cross-platform web-performance page-speed har-analysis yahoo-rules phantomjs bookmarklet nodejs
1 source
- readme: https://github.com/marcelduran/yslow · fetched 2026-08-28 · eca20ce84fd9
Member repositories
| Repository | Role | Health v2 |
|---|---|---|
| marcelduran/yslow | main | 32 |
For agents
markdown · JSON · MCP: product_card(name="marcelduran/yslow")
Data as of 2026-08-30T08:39:29.467469+00:00 · Report a problem