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.
5.12 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
8.32 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
540 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.
5.12 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.
13.02 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS Execution CostAction6963ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.um.es/ | 4385ms | 36ms | 14ms | 3rd |
| Unattributable | 855ms | 194ms | 0ms | 3rd |
| https://www.um.es/combo?browserId=chrome&minifierType=js&languageId=es_ES&t=1773047466764&/o/frontend-js-aui-web/aui/aui/aui-min.js&/o/frontend-js-aui-web/liferay/modules.js&/o/frontend-js-aui-web/liferay/aui_sandbox.js&/o/frontend-js-aui-web/aui/attribute-base/attribute-base-min.js&/o/frontend-js-aui-web/aui/attribute-complex/attribute-complex-min.js&/o/frontend-js-aui-web/aui/attribute-core/attribute-core-min.js&/o/frontend-js-aui-web/aui/attribute-observable/attribute-observable-min.js&/o/frontend-js-aui-web/aui/attribute-extras/attribute-extras-min.js&/o/frontend-js-aui-web/aui/event-custom-base/event-custom-base-min.js&/o/frontend-js-aui-web/aui/event-custom-complex/event-custom-complex-min.js&/o/frontend-js-aui-web/aui/oop/oop-min.js&/o/frontend-js-aui-web/aui/aui-base-lang/aui-base-lang-min.js&/o/frontend-js-aui-web/liferay/dependency.js&/o/frontend-js-aui-web/liferay/util.js&/o/frontend-js-web/liferay/dom_task_runner.js&/o/frontend-js-web/liferay/events.js&/o/frontend-js-web/liferay/lazy_load.js&/o/frontend-js-web/liferay/liferay.js&/o/frontend-js-web/liferay/global.bundle.js&/o/frontend-js-web/liferay/portlet.js&/o/frontend-js-web/liferay/workflow.js&/o/oauth2-provider-web/js/liferay.js | 753ms | 609ms | 34ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-C35G871LG6&cx=c>m=4e64k1 | 384ms | 202ms | 38ms | 3rd |
| https://cdnjs.cloudflare.com/ajax/libs/lottie-web/5.12.2/lottie.min.js | 257ms | 185ms | 20ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TWBMMX | 193ms | 145ms | 38ms | 3rd |
| https://www.um.es/combo?browserId=chrome&minifierType=js&languageId=es_ES&t=1776826903794&/o/frontend-js-jquery-web/jquery/jquery.min.js&/o/frontend-js-jquery-web/jquery/init.js&/o/frontend-js-jquery-web/jquery/ajax.js&/o/frontend-js-jquery-web/jquery/bootstrap.bundle.min.js&/o/frontend-js-jquery-web/jquery/collapsible_search.js&/o/frontend-js-jquery-web/jquery/fm.js&/o/frontend-js-jquery-web/jquery/form.js&/o/frontend-js-jquery-web/jquery/popper.min.js&/o/frontend-js-jquery-web/jquery/side_navigation.js | 135ms | 93ms | 27ms | 3rd |
FJS BundlesAction72 scripts, 335 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtm.js?id=GTM-TWBMMX | 140 KB | 70 KB (50%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-C35G871LG6&cx=c>m=4e64k1 | 157 KB | 66 KB (42%) | ✓ | 3rd |
| https://www.um.es/combo?browserId=chrome&minifierType=js&languageId=es_ES&t=1776826903794&/o/frontend-js-jquery-web/jquery/jquery.min.js&/o/frontend-js-jquery-web/jquery/init.js&/o/frontend-js-jquery-web/jquery/ajax.js&/o/frontend-js-jquery-web/jquery/bootstrap.bundle.min.js&/o/frontend-js-jquery-web/jquery/collapsible_search.js&/o/frontend-js-jquery-web/jquery/fm.js&/o/frontend-js-jquery-web/jquery/form.js&/o/frontend-js-jquery-web/jquery/popper.min.js&/o/frontend-js-jquery-web/jquery/side_navigation.js | 77 KB | 56 KB (73%) | ✗ | 3rd |
| https://www.um.es/combo?browserId=chrome&minifierType=js&languageId=es_ES&t=1773047466764&/o/frontend-js-aui-web/aui/aui/aui-min.js&/o/frontend-js-aui-web/liferay/modules.js&/o/frontend-js-aui-web/liferay/aui_sandbox.js&/o/frontend-js-aui-web/aui/attribute-base/attribute-base-min.js&/o/frontend-js-aui-web/aui/attribute-complex/attribute-complex-min.js&/o/frontend-js-aui-web/aui/attribute-core/attribute-core-min.js&/o/frontend-js-aui-web/aui/attribute-observable/attribute-observable-min.js&/o/frontend-js-aui-web/aui/attribute-extras/attribute-extras-min.js&/o/frontend-js-aui-web/aui/event-custom-base/event-custom-base-min.js&/o/frontend-js-aui-web/aui/event-custom-complex/event-custom-complex-min.js&/o/frontend-js-aui-web/aui/oop/oop-min.js&/o/frontend-js-aui-web/aui/aui-base-lang/aui-base-lang-min.js&/o/frontend-js-aui-web/liferay/dependency.js&/o/frontend-js-aui-web/liferay/util.js&/o/frontend-js-web/liferay/dom_task_runner.js&/o/frontend-js-web/liferay/events.js&/o/frontend-js-web/liferay/lazy_load.js&/o/frontend-js-web/liferay/liferay.js&/o/frontend-js-web/liferay/global.bundle.js&/o/frontend-js-web/liferay/portlet.js&/o/frontend-js-web/liferay/workflow.js&/o/oauth2-provider-web/js/liferay.js | 110 KB | 53 KB (49%) | ✓ | 3rd |
| https://cdnjs.cloudflare.com/ajax/libs/lottie-web/5.12.2/lottie.min.js | 63 KB | 37 KB (59%) | ✓ | 3rd |
| https://www.um.es/o/frontend-taglib-clay/__liferay__/exports/@clayui$core.js | 39 KB | 31 KB (79%) | ✓ | 3rd |
| https://cdn.datatables.net/1.10.11/js/jquery.dataTables.min.js?browserId=chrome&minifierType=js&languageId=es_ES&t=1776849640000 | 27 KB | 22 KB (84%) | ✓ | 3rd |
| https://www.um.es/o/accessibility-settings-state-web/__liferay__/index.js | 1 KB | — | ✓ | 3rd |
| https://www.um.es/o/frontend-js-react-web/__liferay__/exports/react.js | 4 KB | — | ✓ | 3rd |
| https://www.um.es/o/um-lr-74-principal-theme/js/um_mobile_header.js?browserId=chrome&minifierType=js&languageId=es_ES&t=1776849640000 | 0 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
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 InventoryAction119 resources · 1.9 MB · 335 KB savings availableFIX
~335.2 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 119 resources | 1.9 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CPage Weight BudgetAction1.9 MB transferred, 119 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
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
CImage OptimizationAction22 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
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 Loading5 fonts (284 KB)PASS
Web fonts
5
284 KB total
Render-blocking
0
of 5
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
- 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)
Fixing the unchecked items could save ~62 KB and ~124 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall119 requests over 23303msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.um.es www.um.es | Other | 4385ms | 33 KB | — | €48/mo | Costly |
Unattributable Unattributable | Other | 855ms | 0 KB | — | €9/mo | Costly |
www.um.es www.um.es | Other | 753ms | 110 KB | 49% | €8/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 384ms | 157 KB | 42% | €4/mo | Costly |
cdnjs cdnjs.cloudflare.com | CDN | 257ms | 63 KB | 59% | €3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 193ms | 140 KB | 50% | €2/mo | Optional |
www.um.es www.um.es | Other | 135ms | 77 KB | 73% | €1/mo | Optional |
These scripts may cost more than they're worth
- www.um.es adds 4385ms and costs ~€48/month
- Unattributable adds 855ms and costs ~€9/month
- www.um.es adds 753ms and costs ~€8/month
- Google Tag Manager adds 384ms and costs ~€4/month
- cdnjs adds 257ms 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.um.es takes 4385ms 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 855ms 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.um.es takes 753ms 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 384ms 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
cdnjs takes 257ms 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
59% of cdnjs'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
50% of Google Tag Manager'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
73% of www.um.es'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