Skip to content
https://www.mapbox.com

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
66
GRADE
D
FIX
2
REVIEW
1
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 1 REVIEW 2 FIX
F
CO2 Per Page Load
Action
2.13g CO2 per view
FIX
2.13g CO2 per view
Critical::
2.13g CO2 per page view
This page transfers 9.0 MB, producing an estimated 2.13g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.05g, network 0.44g, end-user device 1.63g.
Got: 2.13g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 255.0 kg CO2/year
With 10,000 page views per month, this page would generate approximately 255.0 kg of CO2 annually — equivalent to charging 31880 smartphones.
Info::
Green hosting reduces data center emissions

2.13g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 5% of websites

Sustainable Web Design model v4 · Page size: 9.0 MB

Your site
2.13g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.05g
Network
0.44g
End-user device
1.63g
At 10,000 monthly views: Monthly: 21.3 kg · Annual: 255.0 kg · ≈ 31880 smartphone charges
F
Carbon Budget
Action
95th percentile
FIX
95th percentile
Warning::
2.13g CO2 — above the median website (0.60g)
Heavier than an estimated 5% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 95th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

2.13g

95th percentile

Cleaner than 5% of websites

✗ Above the median website

vs Median 254% more
vs Target 325% more
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A
Green Hosting
Green (cdn)
PASS
Green (cdn)
Info::
Cloudflare CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Cloudflare: 100% renewable energy for global network since 2019
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 Not identified✗CDN Cloudflare✓

Cloudflare: 100% renewable energy for global network since 2019

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 112 KB (vs 9195 KB first visit). 62 of 63 resources are served from browser cache, saving 2.10g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 2.13g)
First visit
9195 KB
Repeat visit
112 KB

99% reduction on repeat visits

Saving 2.10g CO2 per returning visitor

62 resources served from cache · 1 resources re-downloaded

A+
Transfer Efficiency
96% efficient
PASS
96% efficient
Info::
Transfer efficiency: 96%
Only 343 KB of potential savings identified. Your page is well-optimized for size.
96% efficient

Total waste: 343 KB (4% of page weight)

Unused JS 343 KB

0.08g unnecessary CO2 per visit

Actual transfer 9195 KB
Theoretical minimum 8851 KB
Potential savings 343 KB (0.08g CO2)

See Deep Analysis sections above for specific optimizations.

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback