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.
987 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
4.80 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
0 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.132
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.28 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.
4.85 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 BudgetAction5.8 MB transferred, 56 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
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DPage Weight InventoryAction56 resources · 5.8 MB · 63 KB savings availableFIX
~63.1 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 56 resources | 5.8 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction20 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
BJS Execution Cost568ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.up.pt/portal/en/ | 215ms | 12ms | 1ms | 3rd |
| Unattributable | 140ms | 2ms | 0ms | 3rd |
| https://www.up.pt/cdn-cgi/challenge-platform/scripts/jsd/main.js | 133ms | 116ms | 3ms | 3rd |
| https://www.up.pt/cdn-cgi/scripts/7d0fa10a/cloudflare-static/rocket-loader.min.js | 80ms | 56ms | 1ms | 3rd |
BJS Bundles12 scripts, 63 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.up.pt/portal/static/js/jquery/jquery-ui.min.js | 73 KB | 63 KB (87%) | ✓ | 3rd |
| https://www.up.pt/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js | 1 KB | — | ✓ | 3rd |
| https://www.up.pt/cdn-cgi/scripts/7d0fa10a/cloudflare-static/rocket-loader.min.js | 4 KB | — | ✓ | 3rd |
| https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 | 11 KB | — | ✓ | 3rd |
| https://www.up.pt/portal/static/js/project.js | 5 KB | — | ✓ | 3rd |
| https://www.up.pt/portal/static/mobile-sidebar/zeynep.min.js | 1 KB | — | ✓ | 3rd |
| https://www.up.pt/portal/static/js/slick/slick.min.js | 11 KB | — | ✓ | 3rd |
| https://www.up.pt/portal/static/js/bootstrap/bootstrap.bundle.min.js | 23 KB | — | ✓ | 3rd |
| https://cdnjs.cloudflare.com/ajax/libs/lazysizes/5.3.2/lazysizes.min.js | 4 KB | — | ✓ | 3rd |
| https://www.up.pt/portal/static/js/cookieconsent-config.js | 10 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
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 Loading7 fonts (568 KB)PASS
Web fonts
7
568 KB total
Render-blocking
0
of 7
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
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
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 ~214 KB and ~428 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall56 requests over 1563msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.up.pt www.up.pt | Other | 215ms | 34 KB | — | €2/mo | Costly |
Unattributable Unattributable | Other | 140ms | 0 KB | — | €2/mo | Optional |
www.up.pt www.up.pt | Other | 133ms | 0 KB | — | €1/mo | Optional |
www.up.pt www.up.pt | Other | 80ms | 4 KB | — | €1/mo | Optional |
These scripts may cost more than they're worth
- www.up.pt adds 215ms and costs ~€2/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.up.pt takes 215ms 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