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https://zalando.com

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
64
GRADE
D
FIX
2
REVIEW
3
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
6
1 PASS 3 REVIEW 2 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::
AWS: Renewable energy varies by region; committed to 100% by 2025
Info::
AWS CloudFront: Renewable varies by edge location
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 AWS✗CDN AWS CloudFront✗

AWS: Renewable energy varies by region; committed to 100% by 2025

AWS CloudFront: Renewable varies by edge location

Based on known provider commitments. Verify at thegreenwebfoundation.org

D
Carbon Budget
Action
55th percentile
FIX
55th percentile
Warning::
0.79g CO2 — above the median website (0.60g)
Heavier than an estimated 45% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 55th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.79g

55th percentile

Cleaner than 45% of websites

✗ Above the median website

vs Median 32% more
vs Target 58% more
B
CO2 Per Page Load
0.79g CO2 per view
REVIEW
0.79g CO2 per view
Info::
0.79g CO2 per page view
This page transfers 2.8 MB, producing an estimated 0.79g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.15g, network 0.14g, end-user device 0.51g.
Got: 0.79g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 94.9 kg CO2/year
With 10,000 page views per month, this page would generate approximately 94.9 kg of CO2 annually — equivalent to charging 11868 smartphones.

0.79g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 45% of websites

Sustainable Web Design model v4 · Page size: 2.8 MB

Your site
0.79g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.15g
Network
0.14g
End-user device
0.51g
At 10,000 monthly views: Monthly: 7.9 kg · Annual: 94.9 kg · ≈ 11868 smartphone charges
C
Transfer Efficiency
Action
73% efficient
REVIEW
73% efficient
Warning::
Transfer efficiency: 73%
An estimated 762 KB (27%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 762 KB of unused JavaScript. This wasted data produces 0.21g of unnecessary CO2 per page view.
73% efficient

Total waste: 762 KB (27% of page weight)

Unused JS 762 KB

0.21g unnecessary CO2 per visit

Actual transfer 2860 KB
Theoretical minimum 2098 KB
Potential savings 762 KB (0.21g 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+
Repeat Visit Weight
96% cached
PASS
96% cached
Info::
96% reduction on repeat visits
Returning visitors download only 101 KB (vs 2860 KB first visit). 112 of 114 resources are served from browser cache, saving 0.76g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 0.79g)
First visit
2860 KB
Repeat visit
101 KB

96% reduction on repeat visits

Saving 0.76g CO2 per returning visitor

112 resources served from cache · 2 resources re-downloaded

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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