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Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
75
GRADE
C
FIX
4
REVIEW
1
PASS
9
INFO
2

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

Mobile Desktop
29
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
85
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

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

4.67 s

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

12.10 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

2.49 s

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.

9.06 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.

31.69 s

Page Load Progression

474 ms
948 ms
1.4 s
1.9 s
2.4 s
2.8 s
3.3 s
3.8 s
Checks
16
9 PASS 1 REVIEW 4 FIX
F
Page Weight Budget
Action
6.3 MB transferred, 139 requests
FIX
6.3 MB transferred, 139 requests
Critical::
Page weighs 11.7 MB (6.3 MB transferred)
Warning::
JavaScript is 2.1 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 2.1 MB
Warning::
139 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 1.3 g CO2 per page load
6.3 MB / 2.4 MB budget
6.3 MB transferred
139 requests
1.3 g CO2 per page load
JavaScript 2.1 MiB 34%
Other 2.1 MiB 33%
Images 778.8 KiB 12%
Other 504.4 KiB 8%
HTML 268.5 KiB 4%
Fonts 175.2 KiB 3%
Other 170.6 KiB 3%
CSS 116.9 KiB 2%
Other 113.2 KiB 2%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

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

F
JS Execution Cost
Action
16157ms total JS execution
FIX
16157ms total JS execution
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 3713ms CPU time
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 2474ms CPU time
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 2440ms CPU time
Warning::
https://www.deepl.com/en: 2260ms CPU time
Warning::
Unattributable: 1702ms CPU time
Info::
Third-party scripts: 2346ms (15% of total)

Main Thread Breakdown

Script Evaluation 60% Other 21% Style & Layout 8% Script Parsing & Compilation 5%
ScriptTotalScriptingParse/CompileParty
https://www.deepl.com/app-storefront/_next/static/chunks/2296-9ae55c14e86c1e78.js3713ms3298ms60ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/webpack-d2373df64790f017.js2474ms2372ms2ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/2122.03e36ee23dee24f6.js2440ms1737ms26ms1st
https://www.deepl.com/en2260ms71ms69ms1st
Unattributable1702ms96ms0ms3rd
https://www.deepl.com/app-storefront/_next/static/chunks/1dd3208c-db20bb1d8e3bcc9b.js923ms836ms30ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/47bf8baf-2489944084be743a.js755ms430ms46ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/5904.514bfac5c80e25c5.js647ms371ms5ms1st
https://gtm.deepl.com/gtm.js?id=GTM-5F5PGZ5P293ms217ms66ms3rd
https://www.deepl.com/app-storefront/_next/static/chunks/4794-61dfb02280fc97f2.js232ms12ms113ms1st

Showing top 10 of 15 scripts

F
JS Bundles
Action
46 scripts, 528 KB unused
FIX
46 scripts, 528 KB unused
Warning::
https://gtm.deepl.com/gtm.js?id=GTM-5F5PGZ5P: 106 KB unused (50%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 72 KB unused (65%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 61 KB unused (36%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 60 KB unused (16%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 59 KB unused (83%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 528 KB
528 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://gtm.deepl.com/gtm.js?id=GTM-5F5PGZ5P214 KB106 KB (50%)✓3rd
https://www.deepl.com/app-storefront/_next/static/chunks/47bf8baf-2489944084be743a.js111 KB72 KB (65%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/2296-9ae55c14e86c1e78.js173 KB61 KB (36%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/4794-61dfb02280fc97f2.js386 KB60 KB (16%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/2122.03e36ee23dee24f6.js72 KB59 KB (83%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/app/%5Blang%5D/page-e8d7b5e06cbd5eec.js461 KB59 KB (13%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/main-app-2b9713f69aec7991.js97 KB33 KB (34%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/99.8c7b7913f904b9f6.js51 KB31 KB (63%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/6436.bcb23c3434438677.js43 KB25 KB (61%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/8017-c551d3b61f73dc2b.js30 KB21 KB (70%)✓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

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

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

F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

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

C
Image Optimization
Action
23 images, 0 KB saveable
REVIEW
23 images, 0 KB saveable
Warning::
https://www.deepl.com/img/home-experience/customer... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.deepl.com/img/home-experience/logo-clo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.deepl.com/img/home-experience/customer... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.deepl.com/img/home-experience/customer... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.deepl.com/img/home-experience/customer... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
23 images 779 KB
0 oversized -0 KB
16 legacy format
5 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

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

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

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

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

A+
Third-Party Impact
16% third-party, 0 ms blocking
PASS
16% third-party, 0 ms blocking
Info::
Third-party code accounts for 16% of page weight (1.0 MiB of 6.3 MiB)
Info::
Third-party blocking time is low (0 ms)
84%
16%
First-party Third-party
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
3 fonts (175 KB)
PASS
3 fonts (175 KB)
Info::
3 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

3

175 KB total

Render-blocking

0

of 3

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s FCP 4.7 s LCP 12.1 shttps://www.deepl.com/fonts/roboto-regular.woff2roboto-regular.woff2 https://www.deepl.com/fonts/roboto-regular.woff2 — 48.7 KiB — 0 ms — font-display: swaphttps://www.deepl.com/fonts/roboto-light.woff2roboto-light.woff2 https://www.deepl.com/fonts/roboto-light.woff2 — 63.4 KiB — 0 ms — font-display: swaphttps://www.deepl.com/fonts/roboto-medium.woff2roboto-medium.woff2 https://www.deepl.com/fonts/roboto-medium.woff2 — 63.2 KiB — 0 ms — font-display: swap
roboto-regular.woff2 woff2 swap
Size 49 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
roboto-light.woff2 woff2 swap
Size 63 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
roboto-medium.woff2 woff2 swap
Size 63 KB
Load time 0 ms
Start 0 ms
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
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
4 hints, 0 missing preconnects
PASS
4 hints, 0 missing preconnects
Info::
Page uses 4 resource hint(s)

Current Resource Hints

preconnect
—
preload
4
dns-prefetch
—
prefetch
—

4 resource hints configured

A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Network Waterfall
139 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
15% of JavaScript execution is third-party
First-party Third-party 2346ms · 215KB · €25/mo
Unattributable
Other
Costly
Execution 1702ms
Transfer 0 KB
Monthly Cost €18/mo
gtm.deepl.com
Other
Costly
Execution 293ms
Transfer 214 KB
Unused 50%
Monthly Cost €3/mo
challenges.cloudflare.com
Other
Costly
Execution 201ms
Transfer 0 KB
Monthly Cost €2/mo
clearance.deepl.com
Other
Optional
Execution 150ms
Transfer 0 KB
Monthly Cost €2/mo

These scripts may cost more than they're worth

  • Unattributable adds 1702ms and costs ~€18/month
  • gtm.deepl.com adds 293ms and costs ~€3/month
  • challenges.cloudflare.com adds 201ms and costs ~€2/month

Unattributable takes 1702ms 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

gtm.deepl.com takes 293ms 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

challenges.cloudflare.com takes 201ms 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.

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