Performance
· 15 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.
1.65 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.41 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
164 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.
1.98 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.
2.66 s
Page Load Progression
579 ms
1.2 s
1.7 s
2.3 s 2.9 s 3.5 s 4.0 s
4.6 sFPage Weight BudgetAction3.3 MB transferred, 108 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 ImpactAction99% third-party, 0 ms blockingFIX
DJS Execution CostAction2166ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://assets-cdn-s.coub.com/assets/site-b14280a713262d06a8741f014999b8b61b69af8d3b862f54e167430734e77a28.js | 743ms | 396ms | 148ms | 3rd |
| https://assets-cdn-s.coub.com/assets/sync_bundle-bcaff46185690a548a0a5c2ae6bf7869ef4c117525feb11ff66de14d386f731e.js | 396ms | 250ms | 47ms | 3rd |
| Unattributable | 300ms | 20ms | 0ms | 3rd |
| https://mc.yandex.ru/metrika/tag.js | 298ms | 255ms | 12ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-57C6383EJ1&cx=c>m=4e64h1 | 190ms | 142ms | 19ms | 3rd |
| https://coub.com/featured/creators | 176ms | 4ms | 2ms | 1st |
| https://www.googletagmanager.com/gtm.js?id=GTM-MXHWXFG | 64ms | 49ms | 14ms | 3rd |
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 | 452 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 | 85 KB | 45 KB (54%) | ✓ | 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 InventoryAction108 resources · 3.3 MB · 648 KB savings availableFIX
~647.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 108 resources | 3.3 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
Network Waterfall108 requests over 2828msINFO
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 | 743ms | 663 KB | 68% | ₽386/mo | Costly |
assets-cdn-s.coub.com assets-cdn-s.coub.com | Other | 396ms | 210 KB | 12% | ₽206/mo | Costly |
Unattributable Unattributable | Other | 300ms | 0 KB | — | ₽156/mo | Costly |
mc.yandex.ru mc.yandex.ru | Other | 298ms | 85 KB | 54% | ₽155/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 190ms | 160 KB | 40% | ₽99/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 64ms | 121 KB | 51% | ₽33/mo | Optional |
These scripts may cost more than they're worth
- assets-cdn-s.coub.com adds 743ms and costs ~₽386/month
- assets-cdn-s.coub.com adds 396ms and costs ~₽206/month
- Unattributable adds 300ms and costs ~₽156/month
- mc.yandex.ru adds 298ms and costs ~₽155/month
- Google Tag Manager adds 190ms and costs ~₽99/month
92% 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 743ms 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 396ms 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
Unattributable takes 300ms 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 298ms 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
54% 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
Google Tag Manager takes 190ms 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