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.
859 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.58 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
2 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.001
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.09 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.
1.72 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DPage Weight InventoryAction57 resources · 1.3 MB · 202 KB savings availableFIX
~202.0 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 57 resources | 1.3 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BPage Weight Budget1.3 MB transferred, 57 requestsREVIEW
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
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
BImage Optimization21 images, 0 KB saveableREVIEW
BJS Execution Cost565ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.aalto.fi/fi | 308ms | 6ms | 0ms | 3rd |
| https://consent.cookiebot.com/7439002e-4a7e-4422-bda9-d575b2a8d8ce/cc.js?renew=false&referer=www.aalto.fi&dnt=false&init=false&culture=fi | 107ms | 39ms | 8ms | 3rd |
| Unattributable | 85ms | 3ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-N6WP2H | 66ms | 54ms | 11ms | 3rd |
CJS BundlesAction21 scripts, 202 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtm.js?id=GTM-N6WP2H | 163 KB | 78 KB (48%) | ✓ | 3rd |
| https://www.aalto.fi/sites/default/files/js/js_p-4oHC4kUGK5AY3Ml8y7cwkTOo2w_ciFs-aZcFCmXYE.js?scope=footer&delta=10&language=fi&theme=aalto_aaltofi&include=eJx1UlF2hCAMvJCWI_ECRswKhELcXW9frLh1W_sDycy8ZEgA8MIatnMkBeesgwuukIuaR20niA4vJbImfGQSzFrwKYdmCBT1IuRJVnWBNZ2Bgo0OOBBoB95jvqA_F7JzQch2-ksKpwj3Mz6tacLIif1bLQrgULO5oRU90mHXMs-E9YoFo6grsCkHEPCwYlavqDG-jmjZqpcHiZ2q4h-86TlhhGOKe7LN-Wh0X1BlCAN0m4i082zAdz-mpJrSxrOda6sd7hvcN7ipDYt6RZ1jdh61gFOuHr_zD7jB8x0MHcUiEEHjEtQp3myM5Lo0mP0d_feW-n1NamSu3-ILtzP3Pg | 116 KB | 54 KB (46%) | ✓ | 3rd |
| https://www.aalto.fi/sites/default/files/js/js_j6qNKve4SY_QZ1Zc-cP61eJSdM-k7xkKtri8Q6OJN60.js?scope=footer&delta=0&language=fi&theme=aalto_aaltofi&include=eJx1UlF2hCAMvJCWI_ECRswKhELcXW9frLh1W_sDycy8ZEgA8MIatnMkBeesgwuukIuaR20niA4vJbImfGQSzFrwKYdmCBT1IuRJVnWBNZ2Bgo0OOBBoB95jvqA_F7JzQch2-ksKpwj3Mz6tacLIif1bLQrgULO5oRU90mHXMs-E9YoFo6grsCkHEPCwYlavqDG-jmjZqpcHiZ2q4h-86TlhhGOKe7LN-Wh0X1BlCAN0m4i082zAdz-mpJrSxrOda6sd7hvcN7ipDYt6RZ1jdh61gFOuHr_zD7jB8x0MHcUiEEHjEtQp3myM5Lo0mP0d_feW-n1NamSu3-ILtzP3Pg | 84 KB | 50 KB (59%) | ✓ | 3rd |
| https://consent.cookiebot.com/7439002e-4a7e-4422-bda9-d575b2a8d8ce/cc.js?renew=false&referer=www.aalto.fi&dnt=false&init=false&culture=fi | 89 KB | 20 KB (23%) | ✓ | 3rd |
| https://eum.instana.io/eum.min.js | 13 KB | — | ✓ | 3rd |
| https://www.aalto.fi/libraries/photoswipe/dist/photoswipe-ui-default.min.js?tdl4p8 | 4 KB | — | ✓ | 3rd |
| https://www.aalto.fi/sites/default/files/js/js_W7K33Ob2aYND9XTa7TtfXxQQqTynT8HPWP3EZcHZosA.js?scope=footer&delta=5&language=fi&theme=aalto_aaltofi&include=eJx1UlF2hCAMvJCWI_ECRswKhELcXW9frLh1W_sDycy8ZEgA8MIatnMkBeesgwuukIuaR20niA4vJbImfGQSzFrwKYdmCBT1IuRJVnWBNZ2Bgo0OOBBoB95jvqA_F7JzQch2-ksKpwj3Mz6tacLIif1bLQrgULO5oRU90mHXMs-E9YoFo6grsCkHEPCwYlavqDG-jmjZqpcHiZ2q4h-86TlhhGOKe7LN-Wh0X1BlCAN0m4i082zAdz-mpJrSxrOda6sd7hvcN7ipDYt6RZ1jdh61gFOuHr_zD7jB8x0MHcUiEEHjEtQp3myM5Lo0mP0d_feW-n1NamSu3-ILtzP3Pg | 15 KB | — | ✓ | 3rd |
| https://www.aalto.fi/sites/default/files/js/js_VoVHb1KfB24c4I0WT2asC1Cke0dbTX1ZAoydYzyST_0.js?scope=footer&delta=8&language=fi&theme=aalto_aaltofi&include=eJx1UlF2hCAMvJCWI_ECRswKhELcXW9frLh1W_sDycy8ZEgA8MIatnMkBeesgwuukIuaR20niA4vJbImfGQSzFrwKYdmCBT1IuRJVnWBNZ2Bgo0OOBBoB95jvqA_F7JzQch2-ksKpwj3Mz6tacLIif1bLQrgULO5oRU90mHXMs-E9YoFo6grsCkHEPCwYlavqDG-jmjZqpcHiZ2q4h-86TlhhGOKe7LN-Wh0X1BlCAN0m4i082zAdz-mpJrSxrOda6sd7hvcN7ipDYt6RZ1jdh61gFOuHr_zD7jB8x0MHcUiEEHjEtQp3myM5Lo0mP0d_feW-n1NamSu3-ILtzP3Pg | 6 KB | — | ✓ | 3rd |
| https://cdn.jsdelivr.net/npm/js-cookie@3.0.5/dist/js.cookie.min.js | 1 KB | — | ✓ | 3rd |
| https://www.aalto.fi/modules/contrib/google_tag/js/gtm.js?tdl4p8 | 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
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 Loading2 fonts (300 KB)PASS
Web fonts
2
300 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
- 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
- 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 ~240 KB and ~480 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall57 requests over 2534msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.aalto.fi www.aalto.fi | Other | 308ms | 25 KB | — | €3/mo | Costly |
consent.cookiebot.com consent.cookiebot.com | Other | 107ms | 89 KB | 23% | €1/mo | Optional |
Unattributable Unattributable | Other | 85ms | 0 KB | — | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 66ms | 163 KB | 48% | €1/mo | Optional |
These scripts may cost more than they're worth
- www.aalto.fi adds 308ms and costs ~€3/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.aalto.fi takes 308ms 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