Skip to content
https://rtbf.be

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
78
GRADE
C
FIX
1
REVIEW
2
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 2 REVIEW 1 FIX
D
Green Hosting
Action
Not green
FIX
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
Info::
Green hosting status based on known provider commitments
Green hosting detection uses a curated database of provider renewable energy commitments. This is not a real-time verification. For authoritative checks, visit thegreenwebfoundation.org.
Green HostingNot Green Hosted
Hosting Next.js✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

B
Transfer Efficiency
78% efficient
REVIEW
78% efficient
Info::
Transfer efficiency: 78%
An estimated 305 KB (22%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 305 KB of unused JavaScript. This wasted data produces 0.08g of unnecessary CO2 per page view.
78% efficient

Total waste: 305 KB (22% of page weight)

Unused JS 305 KB

0.08g unnecessary CO2 per visit

Actual transfer 1420 KB
Theoretical minimum 1114 KB
Potential savings 305 KB (0.08g CO2)

See Deep Analysis sections above for specific optimizations.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A
CO2 Per Page Load
0.39g CO2 per view
PASS
0.39g CO2 per view
Info::
0.39g CO2 per page view
This page transfers 1.4 MB, producing an estimated 0.39g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.07g, network 0.07g, end-user device 0.25g.
Got: 0.39g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 47.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 47.1 kg of CO2 annually — equivalent to charging 5891 smartphones.

0.39g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 71% of websites

Sustainable Web Design model v4 · Page size: 1.4 MB

Your site
0.39g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.07g
Network
0.07g
End-user device
0.25g
At 10,000 monthly views: Monthly: 3.9 kg · Annual: 47.1 kg · ≈ 5891 smartphone charges
A+
Repeat Visit Weight
85% cached
PASS
85% cached
Info::
85% reduction on repeat visits
Returning visitors download only 207 KB (vs 1420 KB first visit). 108 of 111 resources are served from browser cache, saving 0.34g CO2 per repeat visit.
Info::
Repeat visit: 0.06g CO2 (first visit: 0.39g)
First visit
1420 KB
Repeat visit
207 KB

85% reduction on repeat visits

Saving 0.34g CO2 per returning visitor

108 resources served from cache · 3 resources re-downloaded

A
Carbon Budget
29th percentile
PASS
29th percentile
Info::
0.39g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 71% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 29th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.39g

29th percentile

Cleaner than 71% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 35% cleaner ✓
vs Target 21% cleaner ✓
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback