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.
3.28 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
4.69 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
22 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
1.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.65 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.
6.34 s
Page Load Progression
FPage Weight BudgetAction4.4 MB transferred, 226 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
DJS BundlesAction36 scripts, 191 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 | 71 KB (70%) | ✗ | 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=03ddc136-f784-43c2-a005-a9ac650d0f49&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://www.uw.edu.pl/wp-includes/js/thickbox/thickbox.js | 5 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 InventoryAction226 resources · 4.4 MB · 191 KB savings availableFIX
~190.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 226 resources | 4.4 MiB | ||||||
CImage OptimizationAction99 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
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
CJS Execution CostAction1499ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 401ms | 18ms | 0ms | 3rd |
| https://www.uw.edu.pl/ | 335ms | 35ms | 3ms | 3rd |
| https://www.uw.edu.pl/wp-content/themes/uw/library/js/main.min.js?15032024 | 273ms | 62ms | 11ms | 3rd |
| https://www.uw.edu.pl/wp-content/themes/uw/library/js/jquery/jquery-1.10.2.min.js | 187ms | 141ms | 4ms | 3rd |
| https://cdn.viglink.com/api/vglnk.js | 121ms | 99ms | 6ms | 3rd |
| https://cdn.openshareweb.com/v2/71c6eb22/main.js | 91ms | 80ms | 6ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-B37WHT4SG8&cx=c&_slc=1 | 91ms | 68ms | 23ms | 3rd |
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 Loading3 fonts (148 KB)PASS
Web fonts
3
148 KB total
Render-blocking
0
of 3
Dominant font-display
swap
Most common across fonts
Font loading timeline
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 HintsNo optimization neededPASS
AHTTP Cachingmax-age=3600 (1 hour)PASS
max-age=3600
| Directive | Value | Meaning |
|---|---|---|
| max-age | 3600 | Cache for 1 hour |
Network Waterfall226 requests over 11273msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 401ms | 0 KB | — | zł10/mo | Costly |
www.uw.edu.pl www.uw.edu.pl | Other | 335ms | 44 KB | — | zł8/mo | Costly |
www.uw.edu.pl www.uw.edu.pl | Other | 273ms | 102 KB | 70% | zł7/mo | Costly |
www.uw.edu.pl www.uw.edu.pl | Other | 187ms | 42 KB | — | zł5/mo | Optional |
cdn.viglink.com cdn.viglink.com | Other | 121ms | 29 KB | — | zł3/mo | Optional |
cdn.openshareweb.com cdn.openshareweb.com | Other | 91ms | 41 KB | — | zł2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 91ms | 148 KB | 44% | zł2/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 401ms and costs ~zł10/month
- www.uw.edu.pl adds 335ms and costs ~zł8/month
- www.uw.edu.pl adds 273ms and costs ~zł7/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 401ms 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 335ms 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 273ms 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
70% 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