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.
7.72 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
19.94 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
554 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.
11.64 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.
24.36 s
Page Load Progression
FPage Weight BudgetAction4.3 MB transferred, 204 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
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 ImpactAction100% third-party, 0 ms blockingFIX
FJS Execution CostAction5407ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 1347ms | 89ms | 0ms | 3rd |
| https://www.uw.edu.pl/ | 1100ms | 156ms | 11ms | 3rd |
| https://www.uw.edu.pl/wp-content/themes/uw/library/js/main.min.js?15032024 | 789ms | 228ms | 44ms | 3rd |
| https://www.uw.edu.pl/wp-content/themes/uw/library/js/jquery/jquery-1.10.2.min.js | 643ms | 447ms | 18ms | 3rd |
| https://cdn.viglink.com/api/vglnk.js | 434ms | 358ms | 15ms | 3rd |
| https://cdn.openshareweb.com/v2/71c6eb22/main.js | 358ms | 318ms | 16ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-B37WHT4SG8&cx=c&_slc=1 | 256ms | 192ms | 62ms | 3rd |
| https://commerce-js.sovrn.co/commerce-js.iife.js | 142ms | 123ms | 19ms | 3rd |
| https://cdn.shareaholic.net/assets/pub/shareaholic.js | 117ms | 95ms | 3ms | 3rd |
| https://www.google-analytics.com/analytics.js | 112ms | 95ms | 5ms | 3rd |
Showing top 10 of 11 scripts
DJS BundlesAction36 scripts, 195 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.uw.edu.pl/wp-content/themes/uw/library/js/main.min.js?15032024 | 102 KB | 75 KB (74%) | ✗ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-B37WHT4SG8&cx=c&_slc=1 | 148 KB | 64 KB (44%) | ✓ | 3rd |
| https://commerce-js.sovrn.co/commerce-js.iife.js | 49 KB | 30 KB (62%) | ✓ | 3rd |
| https://ajax.googleapis.com/ajax/libs/angularjs/1.0.1/angular.min.js | 29 KB | 25 KB (89%) | ✓ | 3rd |
| https://partner.shareaholic.com/partners.js?location=https%3A%2F%2Fwww.uw.edu.pl%2F&cl=pl-PL&id_sync=6daff9f7-9aba-42a0-8922-e3be38f41791&pvs=1&site=e0c9d46bb55de0ed369ee3dd661e103e | 1 KB | — | ✓ | 3rd |
| https://www.uw.edu.pl/wp-content/plugins/cookie-law-info/public/js/cookie-law-info-public.js | 7 KB | — | ✓ | 3rd |
| https://www.uw.edu.pl/wp-content/themes/uw/library/js/what-input.min.js | 2 KB | — | ✓ | 3rd |
| https://www.uw.edu.pl/wp-content/themes/uw/library/js/wcag.js | 3 KB | — | ✓ | 3rd |
| https://www.uw.edu.pl/wp-content/themes/uw/library/js/class/class.Core.js?15032024 | 2 KB | — | ✓ | 3rd |
| https://cdnjs.cloudflare.com/ajax/libs/jquery-mousewheel/3.0.6/jquery.mousewheel.min.js | 1 KB | — | ✓ | 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
DPage Weight InventoryAction204 resources · 4.3 MB · 195 KB savings availableFIX
~194.8 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 204 resources | 4.3 MiB | ||||||
CImage OptimizationAction91 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading4 fonts (149 KB)PASS
Web fonts
4
149 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
- 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)
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource Hints9 hints, 0 missing preconnectsPASS
Current Resource Hints
9 resource hints configured
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
AHTTP Cachingmax-age=3600 (1 hour)PASS
max-age=3600
| Directive | Value | Meaning |
|---|---|---|
| max-age | 3600 | Cache for 1 hour |
Network Waterfall204 requests over 10994msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 1347ms | 0 KB | — | zł33/mo | Costly |
www.uw.edu.pl www.uw.edu.pl | Other | 1100ms | 44 KB | — | zł27/mo | Costly |
www.uw.edu.pl www.uw.edu.pl | Other | 789ms | 102 KB | 74% | zł19/mo | Costly |
www.uw.edu.pl www.uw.edu.pl | Other | 643ms | 42 KB | — | zł16/mo | Costly |
cdn.viglink.com cdn.viglink.com | Other | 434ms | 29 KB | — | zł11/mo | Costly |
cdn.openshareweb.com cdn.openshareweb.com | Other | 358ms | 41 KB | — | zł9/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 256ms | 148 KB | 44% | zł6/mo | Costly |
commerce-js.sovrn.co commerce-js.sovrn.co | Other | 142ms | 49 KB | 62% | zł4/mo | Optional |
cdn.shareaholic.net cdn.shareaholic.net | Other | 117ms | 5 KB | — | zł3/mo | Optional |
Google Analytics www.google-analytics.com | Analytics | 112ms | 21 KB | — | zł3/mo | Optional |
www.uw.edu.pl www.uw.edu.pl | Other | 109ms | 7 KB | — | zł3/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 1347ms and costs ~zł33/month
- www.uw.edu.pl adds 1100ms and costs ~zł27/month
- www.uw.edu.pl adds 789ms and costs ~zł19/month
- www.uw.edu.pl adds 643ms and costs ~zł16/month
- cdn.viglink.com adds 434ms and costs ~zł11/month
- cdn.openshareweb.com adds 358ms and costs ~zł9/month
- Google Tag Manager adds 256ms and costs ~zł6/month
100% 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
Unattributable takes 1347ms 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
www.uw.edu.pl takes 1100ms 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
www.uw.edu.pl takes 789ms 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
74% of www.uw.edu.pl'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
www.uw.edu.pl takes 643ms 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
cdn.viglink.com takes 434ms 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
cdn.openshareweb.com takes 358ms 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 256ms 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
62% of commerce-js.sovrn.co'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