Zero tracker, zero cookie
No analytics, no third-party scripts, no Google Fonts. Every outbound request is useful content — no telemetry weighing down each view.
Sustainable IT · Vert Num'
Sustainable web design & carbon footprint
This site weighs a few dozen kilobytes per page and uses no cookies, no remote fonts, no analytics. Here are the real measurements, the applied methodology, and a calculator to test yours.
What this page weighs, right now
Live measurements via the browser Performance API. Reload to refresh.
Transferred weight
—
Ko
Network requests
—
calls
CO₂ per view
—
g eq. CO₂
SWD grade
—
A+ → F scale
Weight includes HTML, CSS, JS, images, fonts, and service workers. CO₂ follows the Sustainable Web Design v4 methodology (0.494 g CO₂ / MB, global network). Our host IONOS is certified green, reducing the footprint by ~9 %.
Website carbon calculator
Estimate a site's annual footprint from three sliders. Based on SWD v4 — same as Website Carbon.
CO₂ per view
—
g eq. CO₂
Per month
—
kg eq. CO₂
Per year
—
kg eq. CO₂
Annual equivalents:
- — km by petrol car
- — trees to plant to offset (1 year)
- — smartphone charges
Best practices applied here
14 sustainable-design measures actually in place on this site. Auditable by opening DevTools.
Service Worker network-first
Pages are cached after the first visit. A returning visitor only re-downloads the changed HTML — assets (CSS, JS, images) are served locally.
Green hosting (IONOS)
IONOS is certified by the Green Web Foundation — data centers running on renewable electricity, with a public PUE commitment.
WebP images + lazy loading
Modern formats (WebP, AVIF when relevant), loading="lazy" attribute, explicit dimensions to avoid CPU/battery-costly reflows.
Minified CSS & JS, single bundle
One styles.min.css and one neural.min.js, no framework. No React/Vue to load — just native DOM and a few AI modules enabled on demand.
System fonts only
No remote @font-face. The system-ui stack reuses fonts already installed — 0 KB to download, 0 latency.
Inline SVG sprites
All icons live in a single SVG sprite <use>. No icon webfont, no multiple PNGs: a few KB for the whole site.
Reading mode (hide HAL)
"Eye" button in the header: cuts the animated neural background and HAL voice. Near-zero CPU/GPU cost for long reads or low batteries.
Respects prefers-reduced-motion
All animations (fade, scale, transitions) are cut if the user has enabled reduced motion. CPU savings and comfort for sensitive people.
AI computed in the browser
Vision, sign language, RAG, Transformers.js: everything runs client-side. No inference server, no network round-trip after model load. Zero cloud energy cost at runtime.
HAL modes enabled on demand
The neural background only appears on "showcase" pages. Content pages (education, contact) have a static background — less GPU load.
HTTP/2 + brotli compression
Request multiplexing, brotli compression on IONOS. Real network weight is ~30 % lower than the transferred weight shown above (brotli measurement).
Speculation Rules API
The browser prefetches likely internal pages (never heavy games) during idle time. Perceived instant, no re-transfer.
Installable PWA, offline-first
Manifest + service worker: the site works offline after the first visit. No wasted re-fetch on poor networks.
Methodology & limitations
Formula used
The calculation follows the Sustainable Web Design v4 model (2024):
CO₂ (g/view) = weight_MB × 0.494 × (new + returning × 0.02)
× (1 − 0.09 if green hosting)Sources: Sustainable Web Design v4, Website Carbon, CO2.js, French RGESN framework.
What this calculation doesn't include
- Manufacturing of the visitor's device (hardware impact amortized over lifetime).
- Embodied energy of the code (dev, CI, review).
- Heat dissipated by visitors' home routers.
The SWD methodology is an approximation intended for teaching and comparison. For an official carbon audit, an ISO 14067 / RGESN assessment is required — which I can carry out on request.