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https://www.erlang.org

Performance

· 13 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
98
GRADE
A+
FIX
0
REVIEW
3
PASS
9
INFO
1

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
100
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
100
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

242 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

349 ms

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.032

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

311 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

352 ms

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
13
9 PASS 3 REVIEW
B
Image Optimization
3 images, 0 KB saveable
REVIEW
3 images, 0 KB saveable
Warning::
https://www.erlang.org/assets/img/eef.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.erlang.org/assets/img/erlang-logo.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
3 images 3 KB
0 oversized -0 KB
2 legacy format
2 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

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

Green Hosting

No green hosting detected

B
HTTP Caching
public,max-age=0,must-revalidate
REVIEW
public,max-age=0,must-revalidate
Info::
Cache-Control header is set
Got: public,max-age=0,must-revalidate
Info::
ETag present — enables conditional (304) responses
Cache-Control

public,max-age=0,must-revalidate

DirectiveValueMeaning
public—Any cache may store this response
max-age0Cache for 0 seconds
must-revalidate—Must recheck with server after expiry
A+
Page Weight Budget
71 KB transferred, 10 requests
PASS
71 KB transferred, 10 requests
Info::
Page weighs 346 KB (71 KB transferred)
Info::
10 HTTP requests
Info::
Estimated 0.01 g CO2 per page load
71 KB / 2.4 MB budget
71 KB transferred
10 requests
0.01 g CO2 per page load
JavaScript 39.6 KiB 56%
Other 12.7 KiB 18%
CSS 10.3 KiB 15%
HTML 5.4 KiB 8%
Images 3.1 KiB 4%
0 2.4 MB 4.9 MB
Under budget
A+
Third-Party Impact
No third-party resources
PASS
No third-party resources
Info::
No third-party resources detected
No third-party resources detected — all resources are first-party.
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
JS Execution Cost
50ms total JS execution
PASS
50ms total JS execution
Info::
https://www.erlang.org/: 50ms CPU time

Main Thread Breakdown

Other 35% Style & Layout 30% Script Evaluation 19% Parse HTML & CSS 7% Script Parsing & Compilation 6% Rendering 4%
ScriptTotalScriptingParse/CompileParty
https://www.erlang.org/50ms1ms0ms1st
A+
Font Loading
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
A+
JS Bundles
3 scripts, 0 KB unused
PASS
3 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.erlang.org/assets/js/prismjs/prism.js16 KB—✓1st
https://www.erlang.org/assets/js/prismjs/components/prism-erlang.js1 KB—✓1st
https://www.erlang.org/assets/js/bootstrap/dist/js/bootstrap.bundle.min.js23 KB—✓1st
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
Network Waterfall
10 requests over 0ms
INFO

Performance analysis not available for this result.

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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