Performance
· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
8.68 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
16.32 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.09 s
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.
8.68 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.
16.52 s
Page Load Progression
375 ms
750 ms 1.1 s 1.5 s 1.9 s 2.2 s
2.6 s 3.0 sFPage Weight BudgetAction2.8 MB transferred, 103 requestsFIX
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction98% third-party, 0 ms blockingFIX
FJS Execution CostAction7030ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://assets-cdn-s.coub.com/assets/site-b14280a713262d06a8741f014999b8b61b69af8d3b862f54e167430734e77a28.js | 2794ms | 1526ms | 521ms | 3rd |
| https://assets-cdn-s.coub.com/assets/sync_bundle-bcaff46185690a548a0a5c2ae6bf7869ef4c117525feb11ff66de14d386f731e.js | 1447ms | 939ms | 179ms | 3rd |
| https://mc.yandex.ru/metrika/tag.js | 1073ms | 942ms | 40ms | 3rd |
| Unattributable | 754ms | 60ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-57C6383EJ1&cx=c>m=4e64h1 | 490ms | 407ms | 76ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-MXHWXFG | 252ms | 197ms | 52ms | 3rd |
| https://coub.com/featured/creators | 221ms | 13ms | 6ms | 1st |
FJS BundlesAction5 scripts, 648 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://assets-cdn-s.coub.com/assets/site-b14280a713262d06a8741f014999b8b61b69af8d3b862f54e167430734e77a28.js | 663 KB | 453 KB (68%) | ✗ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-57C6383EJ1&cx=c>m=4e64h1 | 160 KB | 64 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-MXHWXFG | 121 KB | 62 KB (51%) | ✓ | 3rd |
| https://mc.yandex.ru/metrika/tag.js | 86 KB | 45 KB (53%) | ✓ | 3rd |
| https://assets-cdn-s.coub.com/assets/sync_bundle-bcaff46185690a548a0a5c2ae6bf7869ef4c117525feb11ff66de14d386f731e.js | 210 KB | 25 KB (12%) | ✗ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction103 resources · 2.8 MB · 648 KB savings availableFIX
~648.2 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 103 resources | 2.8 MiB | ||||||
BImage Optimization50 images, 0 KB saveableREVIEW
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
BHTTP Cachingno-cacheREVIEW
no-cache
| Directive | Value | Meaning |
|---|---|---|
| no-cache | — | Cache but always revalidate first |
A+Text CompressionAll text resources are compressedPASS
A+Font Loading2 fonts (47 KB)PASS
Web fonts
2
47 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
Optimization checklist
- Preload critical fonts (priority=high)
- Use woff2 format for all fonts
- Set font-display to swap, optional, or fallback
- Subset large fonts (≤100 KB each)
Fixing the unchecked items could save ~14 KB and ~28 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall103 requests over 2931msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
assets-cdn-s.coub.com assets-cdn-s.coub.com | Other | 2794ms | 663 KB | 68% | ₽1454/mo | Costly |
assets-cdn-s.coub.com assets-cdn-s.coub.com | Other | 1447ms | 210 KB | 12% | ₽753/mo | Costly |
mc.yandex.ru mc.yandex.ru | Other | 1073ms | 86 KB | 53% | ₽558/mo | Costly |
Unattributable Unattributable | Other | 754ms | 0 KB | — | ₽392/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 490ms | 160 KB | 40% | ₽255/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 252ms | 121 KB | 51% | ₽131/mo | Costly |
These scripts may cost more than they're worth
- assets-cdn-s.coub.com adds 2794ms and costs ~₽1454/month
- assets-cdn-s.coub.com adds 1447ms and costs ~₽753/month
- mc.yandex.ru adds 1073ms and costs ~₽558/month
- Unattributable adds 754ms and costs ~₽392/month
- Google Tag Manager adds 490ms and costs ~₽255/month
- Google Tag Manager adds 252ms and costs ~₽131/month
97% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾ ▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
assets-cdn-s.coub.com takes 2794ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
68% of assets-cdn-s.coub.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
assets-cdn-s.coub.com takes 1447ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
mc.yandex.ru takes 1073ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
53% of mc.yandex.ru's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Unattributable takes 754ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 490ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 252ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
51% of Google Tag Manager's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev