Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop

Performance

100

Accessibility

100

Best Practices

100

SEO

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.24 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

2.36 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.

0.013

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

1.92 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.

2.36 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 s

Checks

6 PASS 6 REVIEW 1 FIX

Third-Party Impact

Action

100% third-party, 0 ms blocking

FIX

100% third-party, 0 ms blocking

Third-party code accounts for 100% of page weight (1.3 MiB of 1.3 MiB)

Third-party blocking time is low (0 ms)

100%

First-party Third-party

Page Weight Budget

1.3 MB transferred, 52 requests

REVIEW

1.3 MB transferred, 52 requests

Page weighs 2.3 MB (1.3 MB transferred)

52 HTTP requests

Estimated 0.27 g CO2 per page load

1.3 MB transferred

52 requests

0.27 g CO2 per page load

Images 907.9 KiB 68%

JavaScript 193.6 KiB 15%

Fonts 177.1 KiB 13%

CSS 35.8 KiB 3%

HTML 15.9 KiB 1%

Other 1.3 KiB 0%

Other 324 B 0%

0 2.4 MB 4.9 MB

Under budget

Image Optimization

40 images, 0 KB saveable

REVIEW

40 images, 0 KB saveable

is missing width/height — may cause layout shift

Set explicit width and height to prevent CLS.

40 images 908 KB

0 oversized -0 KB

16 legacy format

1 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

JS Bundles

4 scripts, 106 KB unused

REVIEW

4 scripts, 106 KB unused

https://www.umu.se/Static/umu.js?v=52493967: 62 KB unused (66%)

Consider code splitting or tree shaking to reduce unused code.

https://matomo.analys.cloud/js/container_ihGxGRPo....: 44 KB unused (56%)

Consider code splitting or tree shaking to reduce unused code.

https://www.umu.se/Static/klaro_v0.7.22_no_css.js: unminified — 3 KB could be saved

Total unused JavaScript: 106 KB

106 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://www.umu.se/Static/umu.js?v=52493967	93 KB	62 KB (66%)	✓	3rd
https://matomo.analys.cloud/js/container_ihGxGRPo.js	79 KB	44 KB (56%)	✓	3rd
https://www.umu.se/Static/klaro_v0.7.22_no_css.js	21 KB	—	✗	3rd
https://matomo.analys.cloud/plugins/HeatmapSessionRecording/configs.php?idsite=24&trackerid=vsGY3Y&url=https%3A%2F%2Fwww.umu.se%2F	0 KB	—	✓	3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

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.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Page Weight Inventory

Action

52 resources · 1.3 MB · 106 KB savings available

REVIEW

52 resources · 1.3 MB · 106 KB savings available

Page weight 308 KB over 1MB target

Got: 1.3 MB Expected: ≤ 1 MB

~106 KB of savings available

51 third-party resources (100% of weight)

52 resources · 1.3 MiB · 51 third-party 307.8 KiB over 1MB target

Image 68% · 909.1 KiB

JavaScript 15% · 193.6 KiB

Font 13% · 177.1 KiB

CSS 3% · 35.8 KiB

Document 1% · 15.9 KiB

Other 0% · 380 B

~105.8 KiB of savings available

Remove unused JavaScript: 105.8 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

52 resources			1.3 MiB

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

HTTP Caching

no-cache

REVIEW

no-cache

Cache-Control header is set

Got: no-cache

No ETag or Last-Modified header

Conditional requests (304 Not Modified) are not possible without validators.

Cache-Control

no-cache

Directive	Value	Meaning
no-cache	—	Cache but always revalidate first

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

JS Execution Cost

339ms total JS execution

PASS

339ms total JS execution

https://www.umu.se/: 145ms CPU time

Unattributable: 107ms CPU time

https://www.umu.se/Static/umu.js?v=52493967: 87ms CPU time

Third-party scripts: 339ms (100% of total)

Main Thread Breakdown

Other 29% Script Evaluation 29% Style & Layout 24% Script Parsing & Compilation 7% Rendering 7% Parse HTML & CSS 4%

Script	Total	Scripting	Parse/Compile	Party
https://www.umu.se/	145ms	7ms	1ms	3rd
Unattributable	107ms	6ms	0ms	3rd
https://www.umu.se/Static/umu.js?v=52493967	87ms	63ms	13ms	3rd

A+

Font Loading

3 fonts (177 KB)

PASS

3 fonts (177 KB)

3 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

177 KB total

Render-blocking

of 3

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

GothamSSm-Book_Web.woff2 woff2 swap

Size 59 KB

Load time 748 ms

Start 1.2 s

Risk FOUT — text flashes from fallback to web font

GothamSSm-Bold_Web.woff2 woff2 swap

Size 59 KB

Load time 747 ms

Start 1.2 s

Risk FOUT — text flashes from fallback to web font

GothamSSm-Medium_Web.woff2 woff2 swap

Size 59 KB

Load time 930 ms

Start 1.2 s

Risk FOUT — text flashes from fallback to web font

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 Caching

All resources properly cached

PASS

All resources properly cached

No caching issues found

All static resources have appropriate caching headers.

A+

Critical Rendering Path

No render-blocking resources

PASS

No render-blocking resources

No render-blocking resources detected

A+

Resource Hints

No optimization needed

PASS

No optimization needed

No resource hint issues

Network Waterfall

52 requests over 3481ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Third-Party Script Cost

Per-script blocking time, transfer cost, and cache headers

INFO

100% of JavaScript execution is third-party

First-party Third-party 339ms · 109KB · kr37/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
www.umu.se www.umu.se	Other	145ms	16 KB	—	kr16/mo	Optional
Unattributable Unattributable	Other	107ms	0 KB	—	kr12/mo	Optional
www.umu.se www.umu.se	Other	87ms	93 KB	66%	kr9/mo	Optional

www.umu.se

Other

Optional

Execution 145ms

Transfer 16 KB

Monthly Cost kr16/mo

Unattributable

Other

Optional

Execution 107ms

Transfer 0 KB

Monthly Cost kr12/mo

www.umu.se

Other

Optional

Execution 87ms

Transfer 93 KB

Unused 66%

Monthly Cost kr9/mo

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

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

66% of www.umu.se's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.