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Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
87
GRADE
B
FIX
0
REVIEW
2
PASS
4
INFO
0
Device:
Mobile Desktop
Checks
6
4 PASS 2 REVIEW
B
Transfer Efficiency
82% efficient
REVIEW
82% efficient
Info::
Transfer efficiency: 82%
An estimated 279 KB (18%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 279 KB of unused JavaScript. This wasted data produces 0.06g of unnecessary CO2 per page view.
82% efficient

Total waste: 279 KB (18% of page weight)

Unused JS 279 KB

0.06g unnecessary CO2 per visit

Actual transfer 1521 KB
Theoretical minimum 1242 KB
Potential savings 279 KB (0.06g 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
0.35g CO2 per view
PASS
0.35g CO2 per view
Info::
0.35g CO2 per page view
This page transfers 1.5 MB, producing an estimated 0.35g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.07g, end-user device 0.27g.
Got: 0.35g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 42.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 42.2 kg of CO2 annually — equivalent to charging 5276 smartphones.
Info::
Green hosting reduces data center emissions

0.35g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 75% of websites

Sustainable Web Design model v4 · Page size: 1.5 MB

Your site
0.35g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.07g
End-user device
0.27g
At 10,000 monthly views: Monthly: 3.5 kg · Annual: 42.2 kg · ≈ 5276 smartphone charges
A
Green Hosting
Green (cdn)
PASS
Green (cdn)
Info::
Fastly CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Fastly: 100% renewable energy for edge network
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 Hosting✓ Green Hosted
Hosting Next.js✗CDN Fastly✓

Fastly: 100% renewable energy for edge network

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
92% cached
PASS
92% cached
Info::
92% reduction on repeat visits
Returning visitors download only 123 KB (vs 1521 KB first visit). 70 of 71 resources are served from browser cache, saving 0.32g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 0.35g)
First visit
1521 KB
Repeat visit
123 KB

92% reduction on repeat visits

Saving 0.32g CO2 per returning visitor

70 resources served from cache · 1 resources re-downloaded

A
Carbon Budget
25th percentile
PASS
25th percentile
Info::
0.35g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 75% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 25th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.35g

25th percentile

Cleaner than 75% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 41% cleaner ✓
vs Target 30% cleaner ✓
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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