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https://lib.ru

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
100
GRADE
A+
FIX
1
REVIEW
1
PASS
13
INFO
2

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

Mobile Desktop
56
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
50
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
69
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
83
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.

8.05 s

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

8.05 s

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.

0.000

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

23.86 s

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

8.05 s

Page Load Progression

1.8 s
3.7 s
5.5 s
7.4 s
9.2 s
11.1 s
12.9 s
14.7 s
Checks
17
13 PASS 1 REVIEW 1 FIX
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
Info::
Last-Modified header present

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

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

Green Hosting

No green hosting detected

A+
Page Weight Budget
9 KB transferred, 6 requests
PASS
9 KB transferred, 6 requests
Info::
Page weighs 22 KB (9 KB transferred)
Info::
6 HTTP requests
Info::
Estimated 0.00 g CO2 per page load
9 KB / 2.4 MB budget
9 KB transferred
6 requests
0.00 g CO2 per page load
HTML 8.1 KiB 94%
Other 559 B 6%
Images 0 B 0%
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+
Image Optimization
4 images, 0 KB saveable
PASS
4 images, 0 KB saveable
Info::
All images are well-optimized
4 images 0 KB
0 oversized -0 KB
0 legacy format
0 missing dimensions CLS risk
A+
JS Execution Cost
370ms total JS execution
PASS
370ms total JS execution
Info::
https://lib.ru/: 200ms CPU time
Info::
Unattributable: 170ms CPU time
Info::
Third-party scripts: 170ms (46% of total)

Main Thread Breakdown

Other 42% Style & Layout 34% Rendering 11% Garbage Collection 10%
ScriptTotalScriptingParse/CompileParty
https://lib.ru/200ms1ms0ms1st
Unattributable170ms2ms0ms3rd
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
No JavaScript
PASS
No JavaScript
Info::
No JavaScript bundles
No JavaScript files loaded.
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
A+
Page Weight Inventory
6 resources · 9 KB · 0 KB savings available
PASS
6 resources · 9 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 9 KB
Info::
4 third-party resources (0% of weight)
6 resources · 8.7 KiB · 4 third-party Within 1MB page-weight target
Document 94% · 8.1 KiB
Image 6% · 559 B
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
6 requests over 44928ms
INFO
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s 14.0 s 16.0 s 18.0 s 20.0 s 22.0 s 24.0 s 26.0 s 28.0 s 30.0 s 32.0 s 34.0 s 36.0 s 38.0 s 40.0 s 42.0 s 44.0 s 46.0 s FCP 8.0 s LCP 8.0 shttps://lib.ru// https://lib.ru/ — 200 — 8.1 KiB — 14.7 s — http/1.1https://counter.rambler.ru/top100.cnt?59291counter.rambler.ru/top100.cnt?59291 https://counter.rambler.ru/top100.cnt?59291 — -1 — 0 B — 30.2 s — https://top.list.ru/counter?id=105282;t=99top.list.ru/counter?id=105282;t=99 https://top.list.ru/counter?id=105282;t=99 — -1 — 0 B — 325 ms — https://top100-images.rambler.ru/top100/b0.giftop100-images.rambler.ru/top100/b0.... https://top100-images.rambler.ru/top100/b0.gif — -1 — 0 B — 448 ms — https://u083.69.spylog.com/cnt?p=0u083.69.spylog.com/cnt?p=0 https://u083.69.spylog.com/cnt?p=0 — -1 — 0 B — 56 ms — https://lib.ru/favicon.ico/favicon.ico https://lib.ru/favicon.ico — 200 — 559 B — 82 ms — http/1.1
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
46% of JavaScript execution is third-party
First-party Third-party 170ms · 0KB · ₽50/mo
Unattributable
Other
Costly
Execution 170ms
Transfer 0 KB
Monthly Cost ₽50/mo

These scripts may cost more than they're worth

  • Unattributable adds 170ms and costs ~₽50/month

46% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

Unattributable takes 170ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

How third-party costs are calculated

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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