Skip to content
https://nubank.com.br

Sustainability

· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
65
GRADE
D
FIX
3
REVIEW
3
PASS
1
INFO
1
Device:
Mobile Desktop
Checks
8
1 PASS 3 REVIEW 3 FIX
D
CO2 Per Page Load
Action
0.95g CO2 per view
FIX
0.95g CO2 per view
Info::
0.95g CO2 per page view
This page transfers 3.4 MB, producing an estimated 0.95g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.18g, network 0.16g, end-user device 0.61g.
Got: 0.95g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 114.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 114.5 kg of CO2 annually — equivalent to charging 14317 smartphones.

0.95g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 40% of websites

Sustainable Web Design model v4 · Page size: 3.4 MB

Your site
0.95g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.18g
Network
0.16g
End-user device
0.61g
At 10,000 monthly views: Monthly: 9.5 kg · Annual: 114.5 kg · ≈ 14317 smartphone charges
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
60th percentile
FIX
60th percentile
Warning::
0.95g CO2 — above the median website (0.60g)
Heavier than an estimated 40% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 60th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.95g

60th percentile

Cleaner than 40% of websites

✗ Above the median website

vs Median 59% more
vs Target 91% more
C
Transfer Efficiency
Action
72% efficient
REVIEW
72% efficient
Warning::
Transfer efficiency: 72%
An estimated 961 KB (28%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 961 KB of unused JavaScript. This wasted data produces 0.27g of unnecessary CO2 per page view.
72% efficient

Total waste: 961 KB (28% of page weight)

Unused JS 961 KB

0.27g unnecessary CO2 per visit

Actual transfer 3451 KB
Theoretical minimum 2490 KB
Potential savings 961 KB (0.27g CO2)

See Deep Analysis sections above for specific optimizations.

B
Web Font Weight Variants
No detectable Google Fonts weights
REVIEW
No detectable Google Fonts weights
Info::
No detectable Google Fonts weights
The analyzer detects font weights via Google Fonts URL parameters (~70% of font-using sites). Self-hosted fonts and non-Google CDN fonts aren't visible to URL-based detection. If you self-host fonts, manually audit how many @font-face weights you ship -- 2-3 weights per family is typically enough; 5+ is usually unused payload.
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Repeat Visit Weight
97% cached
PASS
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 104 KB (vs 3451 KB first visit). 135 of 138 resources are served from browser cache, saving 0.93g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 0.95g)
First visit
3451 KB
Repeat visit
104 KB

97% reduction on repeat visits

Saving 0.93g CO2 per returning visitor

135 resources served from cache · 3 resources re-downloaded

Image Optimization
17 images, 532 KB total, 279 KB wasted
INFO

Image Optimization Audit

Total Images

17

Total Size

532 KB

Oversized

5

Wasted

279 KB

4 missing alt text 13 missing dimensions 6 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback