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.
3.23 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
3.68 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
60 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.355
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
3.23 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.
3.88 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 sDThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS Execution CostAction2046ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.uio.no/ | 533ms | 27ms | 4ms | 3rd |
| https://www.uio.no/vrtx/dist/resources/uio2/js/jquery.min.js?x-h=1774601544824 | 519ms | 290ms | 16ms | 3rd |
| Unattributable | 508ms | 23ms | 0ms | 3rd |
| https://www.uio.no/vrtx/dist/resources/uio2/css/style2.css?x-h=1774601544824 | 219ms | 0ms | 0ms | 3rd |
| https://www.uio.no/vrtx/dist/resources/uio2/js/statistics-new.js | 169ms | 103ms | 0ms | 3rd |
| https://www.uio.no/vrtx/dist/resources/js/consent.js?x-h=1774601544824 | 99ms | 21ms | 6ms | 3rd |
CImage OptimizationAction23 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
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
APage Weight Budget858 KB transferred, 50 requestsPASS
A+Text CompressionAll text resources are compressedPASS
A+Font LoadingNo web fonts (system fonts)PASS
AJS Bundles22 scripts, 43 KB unusedPASS
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.uio.no/vrtx/dist/resources/uio2/js/uio2.js | 59 KB | 43 KB (74%) | ✓ | 3rd |
| https://www.uio.no/vrtx/dist/resources/uio2/js/canvas.js | 0 KB | — | ✓ | 3rd |
| https://www.uio.no/vrtx/dist/resources/uio2/js/puzzel-chatbot.js | 1 KB | — | ✓ | 3rd |
| https://vrtx.uio.no/js/analytics/v2/uioGa.js | 7 KB | — | ✗ | 3rd |
| https://www.uio.no/vrtx/__vrtx/app-services/external-network.js | 0 KB | — | ✓ | 3rd |
| https://vrtx.uio.no/js/analytics/v2/www.uio.no/customTracker.js | 1 KB | — | ✓ | 3rd |
| https://www.uio.no/vrtx/__vrtx/app-services/internal-network.js | 0 KB | — | ✓ | 3rd |
| https://vrtx.uio.no/js/analytics/v3/analytics.js | 25 KB | — | ✓ | 3rd |
| https://www.uio.no/vrtx/dist/resources/uio2/js/big-project.js | 1 KB | — | ✓ | 3rd |
| https://www.uio.no/vrtx/dist/resources/uio2/js/studies.js | 4 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
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
APage Weight Inventory50 resources · 858 KB · 43 KB savings availablePASS
~43.5 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 50 resources | 857.7 KiB | ||||||
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
AHTTP Cachingmax-age=86400 (1 day)PASS
max-age=86400, stale-while-revalidate=21600, stale-if-error=31536000
| Directive | Value | Meaning |
|---|---|---|
| max-age | 86400 | Cache for 1 day |
| stale-while-revalidate | 21600 | Serve stale for 6 hours while fetching fresh |
| stale-if-error | 31536000 |
Network Waterfall50 requests over 1007msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.uio.no www.uio.no | Other | 533ms | 8 KB | — | kr66/mo | Costly |
www.uio.no www.uio.no | Other | 519ms | 34 KB | — | kr64/mo | Costly |
Unattributable Unattributable | Other | 508ms | 0 KB | — | kr63/mo | Costly |
www.uio.no www.uio.no | Other | 219ms | 100 KB | — | kr27/mo | Costly |
www.uio.no www.uio.no | Other | 169ms | 4 KB | — | kr21/mo | Optional |
www.uio.no www.uio.no | Other | 99ms | 5 KB | — | kr12/mo | Optional |
These scripts may cost more than they're worth
- www.uio.no adds 533ms and costs ~kr66/month
- www.uio.no adds 519ms and costs ~kr64/month
- Unattributable adds 508ms and costs ~kr63/month
- www.uio.no adds 219ms and costs ~kr27/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
www.uio.no takes 533ms 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.uio.no takes 519ms 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 508ms 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.uio.no takes 219ms 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