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

Accessibility

100

Best Practices

SEO

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

624 ms

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

1.44 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.

0.053

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

629 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

1.48 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

7 PASS 4 REVIEW 2 FIX

Page Weight Budget

Action

31.0 MB transferred, 122 requests

FIX

31.0 MB transferred, 122 requests

Page weighs 33.1 MB (31.0 MB transferred)

Images are 1.6 MB — compress or use modern formats

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Got: 1.6 MB

Fonts are 226 KB — consider subsetting or using system fonts

Subset fonts to include only used characters, or switch to system font stacks.

Got: 226 KB

CSS is 211 KB — consider purging unused styles

Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.

Got: 211 KB

122 HTTP requests — consider bundling or reducing

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Estimated 6.5 g CO2 per page load

31.0 MB transferred

122 requests

6.5 g CO2 per page load

Other 28.8 MiB 93%

Images 1.6 MiB 5%

Fonts 226.2 KiB 1%

CSS 211.4 KiB 1%

JavaScript 178.3 KiB 1%

HTML 39.7 KiB 0%

Other 560 B 0%

Other 144 B 0%

0 2.4 MB 4.9 MB

Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

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.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.

Why this matters

CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.

Source: web.dev

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

HTTP Caching

Action

No cache headers

FIX

No cache headers

No Cache-Control header found

Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

Last-Modified header present

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

Image Optimization

84 images, 0 KB saveable

REVIEW

84 images, 0 KB saveable

https://nextcloud.com/c/uploads/2026/01/instant-tr... is missing width/height — may cause layout shift

Set explicit width and height to prevent CLS.

84 images 1.6 MB

0 oversized -0 KB

52 legacy format

1 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

JS Execution Cost

909ms total JS execution

REVIEW

909ms total JS execution

Unattributable: 498ms CPU time

https://nextcloud.com/: 411ms CPU time

Third-party scripts: 498ms (55% of total)

Main Thread Breakdown

Other 59% Style & Layout 17% Script Evaluation 10% Rendering 6% Parse HTML & CSS 5%

Script	Total	Scripting	Parse/Compile	Party
Unattributable	498ms	9ms	0ms	3rd
https://nextcloud.com/	411ms	37ms	3ms	1st

JS Bundles

Action

10 scripts, 73 KB unused

REVIEW

10 scripts, 73 KB unused

https://nextcloud.com/wp-includes/js/jquery/jquery...: 51 KB unused (62%)

Consider code splitting or tree shaking to reduce unused code.

https://nextcloud.com/wp-includes/js/jquery/jquery...: unminified — 42 KB could be saved

https://cdn.matomo.cloud/nextcloud.matomo.cloud/co...: 23 KB unused (45%)

Consider code splitting or tree shaking to reduce unused code.

https://nextcloud.com/wp-includes/js/jquery/jquery...: unminified — 4 KB could be saved

Total unused JavaScript: 73 KB

73 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://nextcloud.com/wp-includes/js/jquery/jquery.js?ver=3.7.1	82 KB	51 KB (62%)	✗	1st
https://cdn.matomo.cloud/nextcloud.matomo.cloud/container_wlmEL4w2.js	50 KB	23 KB (45%)	✓	3rd
https://nextcloud.com/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	10 KB	—	✗	1st
https://nextcloud.com/c/themes/nextcloud-theme/dist/js/jquery.magnific-popup.min.js?ver=1	7 KB	—	✓	1st
https://nextcloud.com/c/themes/nextcloud-theme/dist/js/jquery.sticky-sidebar.min.js?ver=1	4 KB	—	✓	1st
https://nextcloud.com/c/themes/nextcloud-theme/dist/js/nc_cookies.js?ver=1	7 KB	—	✗	1st
https://nextcloud.com/c/themes/nextcloud-theme/dist/js/purify.min.js?ver=1	8 KB	—	✓	1st
https://nextcloud.com/c/themes/nextcloud-theme/dist/js/cookie_banner_script.js?ver=1	3 KB	—	✓	1st
https://nextcloud.com/c/themes/nextcloud-theme/dist/js/critical_scripts.js?ver=1	1 KB	—	✓	1st
https://nextcloud.com/p/wp-rocket/assets/js/lazyload/17.8.3/lazyload.js	6 KB	—	✓	1st

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

122 resources · 31.0 MB · 73 KB savings available

REVIEW

122 resources · 31.0 MB · 73 KB savings available

Page weight 30.0 MB over 1MB target

Got: 31.0 MB Expected: ≤ 1 MB

~73 KB of savings available

17 third-party resources (0% of weight)

12 resources over 200KB

122 resources · 31.0 MiB · 17 third-party 30.0 MiB over 1MB target

Media 93% · 28.8 MiB

Image 5% · 1.6 MiB

Font 1% · 226.2 KiB

CSS 1% · 211.4 KiB

JavaScript 1% · 178.3 KiB

Document 0% · 39.7 KiB

Other 0% · 144 B

~73.0 KiB of savings available

Remove unused JavaScript: 73.0 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

122 resources			31.0 MiB

A+

Third-Party Impact

0% third-party, 0 ms blocking

PASS

0% third-party, 0 ms blocking

Third-party code accounts for 0% of page weight (50.6 KiB of 31.0 MiB)

Third-party blocking time is low (0 ms)

100%

First-party Third-party

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

Font Loading

4 fonts (226 KB)

PASS

4 fonts (226 KB)

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

Web fonts

226 KB total

Render-blocking

of 4

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

inter-v19-latin-700.woff2 woff2 swap

Size 24 KB

Load time 32 ms

Start 458 ms

Risk FOUT — text flashes from fallback to web font

inter-v19-latin-regular... woff2 swap

Size 23 KB

Load time 30 ms

Start 458 ms

Risk FOUT — text flashes from fallback to web font

inter-v19-latin-italic.... woff2 swap

Size 25 KB

Load time 44 ms

Start 568 ms

Risk FOUT — text flashes from fallback to web font

fa-solid-900.woff2 woff2 swap

Size 155 KB

Load time 403 ms

Start 627 ms

Risk FOUT — text flashes from fallback to web font

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 ~77 KB and ~154 ms

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

A+

Green Hosting

Whether the site is served from green-energy infrastructure

PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Hetzner Online GmbH

Network Waterfall

122 requests over 1227ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Third-Party Script Cost

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

INFO

55% of JavaScript execution is third-party

First-party Third-party 498ms · 0KB · $7/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
Unattributable Unattributable	Other	498ms	0 KB	—	$7/mo	Costly

Unattributable

Other

Costly

Execution 498ms

Transfer 0 KB

Monthly Cost $7/mo

These scripts may cost more than they're worth

Unattributable adds 498ms and costs ~$7/month

55% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

Unattributable takes 498ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

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.