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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
75
GRADE
C
FIX
4
REVIEW
1
PASS
7
INFO
2

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

Mobile Desktop
34
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
86
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.

1.68 s

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

4.96 s

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

1.04 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.044

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

3.65 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.

6.75 s

Page Load Progression

672 ms
1.3 s
2.0 s
2.7 s
3.4 s
4.0 s
4.7 s
5.4 s
Checks
14
7 PASS 1 REVIEW 4 FIX
F
Page Weight Budget
Action
6.0 MB transferred, 136 requests
FIX
6.0 MB transferred, 136 requests
Critical::
Page weighs 11.3 MB (6.0 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::
136 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
6.0 MB / 2.4 MB budget
6.0 MB transferred
136 requests
1.3 g CO2 per page load
JavaScript 2.1 MiB 35%
Other 2.1 MiB 35%
Other 538.2 KiB 9%
Images 433.4 KiB 7%
HTML 267.0 KiB 4%
Fonts 175.2 KiB 3%
Other 171.1 KiB 3%
CSS 117.9 KiB 2%
Other 112.9 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
5295ms total JS execution
FIX
5295ms total JS execution
Warning::
Unattributable: 1348ms CPU time
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 945ms CPU time
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 915ms CPU time
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 693ms CPU time
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 443ms CPU time
Info::
Third-party scripts: 1435ms (27% of total)

Main Thread Breakdown

Script Evaluation 44% Other 41% Style & Layout 7% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
Unattributable1348ms26ms0ms3rd
https://www.deepl.com/app-storefront/_next/static/chunks/47bf8baf-2489944084be743a.js945ms158ms10ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/2296-9ae55c14e86c1e78.js915ms773ms14ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/webpack-d2373df64790f017.js693ms669ms1ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/2122.03e36ee23dee24f6.js443ms314ms5ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/1dd3208c-db20bb1d8e3bcc9b.js268ms180ms8ms1st
https://www.deepl.com/en240ms11ms11ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/5904.514bfac5c80e25c5.js209ms96ms1ms1st
https://www.deepl.com/app-storefront/_next/static/chunks/4794-61dfb02280fc97f2.js96ms4ms27ms1st
https://gtm.deepl.com/gtm.js?id=GTM-5F5PGZ5P87ms66ms19ms3rd

Showing top 10 of 11 scripts

F
JS Bundles
Action
46 scripts, 530 KB unused
FIX
46 scripts, 530 KB unused
Warning::
https://gtm.deepl.com/gtm.js?id=GTM-5F5PGZ5P: 107 KB unused (50%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 73 KB unused (65%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.deepl.com/app-storefront/_next/static/...: 62 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/...: 60 KB unused (83%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 530 KB
530 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://gtm.deepl.com/gtm.js?id=GTM-5F5PGZ5P215 KB107 KB (50%)✓3rd
https://www.deepl.com/app-storefront/_next/static/chunks/47bf8baf-2489944084be743a.js112 KB73 KB (65%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/2296-9ae55c14e86c1e78.js173 KB62 KB (36%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/4794-61dfb02280fc97f2.js385 KB60 KB (16%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/2122.03e36ee23dee24f6.js73 KB60 KB (83%)✓1st
https://www.deepl.com/app-storefront/_next/static/chunks/app/%5Blang%5D/page-e8d7b5e06cbd5eec.js462 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.js50 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
24 images, 0 KB saveable
REVIEW
24 images, 0 KB saveable
Warning::
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.
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.
24 images 433 KB
0 oversized -0 KB
16 legacy format
6 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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
17% third-party, 0 ms blocking
PASS
17% third-party, 0 ms blocking
Info::
Third-party code accounts for 17% of page weight (1.0 MiB of 6.0 MiB)
Info::
Third-party blocking time is low (0 ms)
83%
17%
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 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 1.7 s LCP 5.0 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
No optimization needed
PASS
No optimization needed
Info::
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: Cloudflare

Network Waterfall
136 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
27% of JavaScript execution is third-party
First-party Third-party 1435ms · 215KB · €16/mo
Unattributable
Other
Costly
Execution 1348ms
Transfer 0 KB
Monthly Cost €15/mo
gtm.deepl.com
Other
Optional
Execution 87ms
Transfer 215 KB
Unused 50%
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • Unattributable adds 1348ms and costs ~€15/month

Unattributable takes 1348ms 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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