About WSG Check
An open-source tool for evaluating websites against the W3C Web Sustainability Guidelines (WSG) .
Purpose & Methodology
WSG Check analyses a web page's HTML and HTTP responses against 80+ automated and semi-automated checks derived from the W3C Web Sustainability Guidelines. Each check maps to a specific guideline and provides a pass, fail, warn, or info result along with an actionable recommendation.
Because WSG Check uses static analysis only (no headless browser), some checks that require JavaScript execution or network timing — such as Core Web Vitals — are out of scope. Those are flagged in every report with links to complementary tools like Google PageSpeed Insights .
How Scoring Works
Each check contributes a score of 0–100, weighted by impact (high, medium, low). The overall sustainability score is a weighted average across all scored checks. Checks with status info or not-applicable are excluded from the average.
Grade A
Score 90–100
Grade B
Score 75–89
Grade C
Score 60–74
Grade D
Score 45–59
Grade F
Score 0–44
Sustainability Statement
WSG Check is itself designed to minimise environmental impact:
- Static analysis only — no headless browser, no Chromium binary
- Zero third-party JavaScript on the frontend (Park UI + PandaCSS generate static CSS)
- Server-side rendering for fast initial load with minimal client-side hydration
- In-memory result store with automatic TTL eviction (no database)
- Follows W3C Web Sustainability Guidelines in its own implementation