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https://www.deezer.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
80
GRADE
B
FIX
4
REVIEW
3
PASS
7
INFO
2

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

Mobile Desktop
48
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
57
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
85
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.

6.88 s

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

12.29 s

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

420 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.

7.34 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.

12.42 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
16
7 PASS 3 REVIEW 4 FIX
D
Page Weight Budget
Action
2.3 MB transferred, 52 requests
FIX
2.3 MB transferred, 52 requests
Info::
Page weighs 5.5 MB (2.3 MB transferred)
Warning::
JavaScript is 880 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 880 KB
Info::
Fonts are 357 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 357 KB
Info::
52 HTTP requests
Info::
Estimated 0.49 g CO2 per page load
2.3 MB / 2.4 MB budget
2.3 MB transferred
52 requests
0.49 g CO2 per page load
Images 972.4 KiB 41%
JavaScript 880.3 KiB 37%
Fonts 357.4 KiB 15%
Other 98.8 KiB 4%
HTML 51.0 KiB 2%
CSS 30.3 KiB 1%
Other 4.4 KiB 0%
Other 1.9 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Approaching limit

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

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

D
Third-Party Impact
Action
89% third-party, 0 ms blocking
FIX
89% third-party, 0 ms blocking
Warning::
Third-party code accounts for 89% of page weight (2.1 MiB of 2.3 MiB)
Info::
Third-party blocking time is low (0 ms)
89%
First-party Third-party
D
JS Execution Cost
Action
2786ms total JS execution
FIX
2786ms total JS execution
Warning::
https://www.deezer.com/CF6YEld6/91qK8Zv/WnnBwoW/9n...: 772ms CPU time
Warning::
Unattributable: 455ms CPU time
Warning::
https://surveys-static-prd.survicate-cdn.com/widge...: 384ms CPU time
Warning::
https://qb3mmcu0z3.kameleoon.io/engine.js: 328ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-PPQ...: 301ms CPU time
Warning::
Third-party scripts: 1855ms (67% of total)

Main Thread Breakdown

Script Evaluation 64% Other 16% Script Parsing & Compilation 11% Style & Layout 7%
ScriptTotalScriptingParse/CompileParty
https://www.deezer.com/CF6YEld6/91qK8Zv/WnnBwoW/9n/E9kazL3Gwiu9Dp3Vb3/ChhnPnsWAg/TARDaxs2/DTsB772ms625ms43ms1st
Unattributable455ms59ms0ms3rd
https://surveys-static-prd.survicate-cdn.com/widget_core-28.22.7.js384ms243ms68ms3rd
https://qb3mmcu0z3.kameleoon.io/engine.js328ms265ms21ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-PPQNZ6301ms231ms67ms3rd
https://cdn-files.dzcdn.net/cache/js/app-backstage-plain-html.1de236d206f16f2e8525.js160ms119ms32ms3rd
https://cdn-assets.dzcdn.net/common/js/gdpr-appliance.js125ms88ms36ms3rd
https://www.deezer.com/us/100ms13ms4ms1st
https://www.deezer.com/CF6YEld6/91qK8Zv/WnnBwoW/9n/VrkaOm/A3xPPnsWAg/ShoucH4O/Tl8p58ms48ms6ms1st
https://cdn.segment.com/next-integrations/actions/3962/1faa179dfb20d0a3f5a0.js51ms45ms3ms3rd

Showing top 10 of 11 scripts

D
HTTP Caching
Action
no-store (uncacheable)
FIX
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: no-store, no-cache, must-revalidate
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

no-store, no-cache, must-revalidate

DirectiveValueMeaning
no-store—Never cache this response
no-cache—Cache but always revalidate first
must-revalidate—Must recheck with server after expiry
B
Image Optimization
8 images, 0 KB saveable
REVIEW
8 images, 0 KB saveable
Warning::
https://cdn-assets.dzcdn.net/common/images/apple-s... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn-assets.dzcdn.net/common/images/play-st... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
8 images 972 KB
0 oversized -0 KB
3 legacy format
2 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

C
JS Bundles
Action
16 scripts, 252 KB unused
REVIEW
16 scripts, 252 KB unused
Warning::
https://surveys-static-prd.survicate-cdn.com/widge...: 76 KB unused (48%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-PPQ...: 70 KB unused (39%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn-files.dzcdn.net/cache/js/app-backstage...: 68 KB unused (61%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.deezer.com/CF6YEld6/91qK8Zv/WnnBwoW/9n...: 38 KB unused (21%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 252 KB
252 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://surveys-static-prd.survicate-cdn.com/widget_core-28.22.7.js160 KB76 KB (48%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-PPQNZ6182 KB70 KB (39%)✓3rd
https://cdn-files.dzcdn.net/cache/js/app-backstage-plain-html.1de236d206f16f2e8525.js113 KB68 KB (61%)✓3rd
https://www.deezer.com/CF6YEld6/91qK8Zv/WnnBwoW/9n/E9kazL3Gwiu9Dp3Vb3/ChhnPnsWAg/TARDaxs2/DTsB182 KB38 KB (21%)✓1st
https://cdn-files.dzcdn.net/cache/js/schemaFilter.dd5daaa6c48397b27316.js1 KB—✓3rd
https://cdn-files.dzcdn.net/cache/js/bocal-en-US.4da0672db0fee6784d4d.js27 KB—✓3rd
https://cdn-assets.dzcdn.net/common/js/gdpr-appliance/index.972f32186a401ccfc6feaad320d0045dd03e93ee.js89 KB—✓3rd
https://cdn-files.dzcdn.net/cache/js/ajs-destination.9456684c162e3b4e9bd3.js3 KB—✓3rd
https://qb3mmcu0z3.kameleoon.io/engine.js43 KB—✓3rd
https://cdn.segment.com/next-integrations/actions/braze-cloud-plugins/c3dbe2dde9d1804663f0.js2 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

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

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

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
6 fonts (357 KB)
PASS
6 fonts (357 KB)
Info::
6 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

6

357 KB total

Render-blocking

0

of 6

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 6.9 s LCP 12.3 shttps://cdn-assets.dzcdn.net/common/fonts/deezer-brand/deezer-brand-bold.31cd34a97d9c1093dae0cd962ecbf6dbc3034163.woff2deezer-brand-bold.31cd3... https://cdn-assets.dzcdn.net/common/fonts/deezer-brand/deezer-brand-bold.31cd34a97d9c1093dae0cd962ecbf6dbc3034163.woff2 — 64.9 KiB — 0 ms — font-display: swaphttps://cdn-assets.dzcdn.net/common/fonts/deezer-brand/deezer-brand-extrabold.d9e833eeea6de8cf9ca90a48edf5ab1e4db5db42.woff2deezer-brand-extrabold.... https://cdn-assets.dzcdn.net/common/fonts/deezer-brand/deezer-brand-extrabold.d9e833eeea6de8cf9ca90a48edf5ab1e4db5db42.woff2 — 63.3 KiB — 0 ms — font-display: swaphttps://cdn-assets.dzcdn.net/common/fonts/inter/inter-semibold.621d67ce7463019c98c7473ab8677841ff24b1fd.woff2inter-semibold.621d67ce... https://cdn-assets.dzcdn.net/common/fonts/inter/inter-semibold.621d67ce7463019c98c7473ab8677841ff24b1fd.woff2 — 60.6 KiB — 0 ms — font-display: swaphttps://cdn-assets.dzcdn.net/common/fonts/inter/inter-medium.3f7a742daef8d40e07155f98f56b44fe7a191d94.woff2inter-medium.3f7a742dae... https://cdn-assets.dzcdn.net/common/fonts/inter/inter-medium.3f7a742daef8d40e07155f98f56b44fe7a191d94.woff2 — 52.3 KiB — 0 ms — font-display: swaphttps://cdn-assets.dzcdn.net/common/fonts/inter/inter-regular.e226d8e173551f5742af606dc1d0b184fe38ef38.woff2inter-regular.e226d8e17... https://cdn-assets.dzcdn.net/common/fonts/inter/inter-regular.e226d8e173551f5742af606dc1d0b184fe38ef38.woff2 — 55.4 KiB — 0 ms — font-display: swaphttps://cdn-assets.dzcdn.net/common/fonts/inter/inter-bold.041da318cff68d04380ea1e5d16390c5de1fa47d.woff2inter-bold.041da318cff6... https://cdn-assets.dzcdn.net/common/fonts/inter/inter-bold.041da318cff68d04380ea1e5d16390c5de1fa47d.woff2 — 60.9 KiB — 0 ms — font-display: swap
deezer-brand-bold.31cd3... woff2 swap
Size 65 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
deezer-brand-extrabold.... woff2 swap
Size 63 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
inter-semibold.621d67ce... woff2 swap
Size 61 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
inter-medium.3f7a742dae... woff2 swap
Size 52 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
inter-regular.e226d8e17... woff2 swap
Size 55 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
inter-bold.041da318cff6... woff2 swap
Size 61 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
7 hints, 0 missing preconnects
PASS
7 hints, 0 missing preconnects
Info::
Page uses 7 resource hint(s)

Current Resource Hints

preconnect
1
preload
6
dns-prefetch
—
prefetch
—

7 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
Network Waterfall
52 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
67% of JavaScript execution is third-party
First-party Third-party 1855ms · 530KB · $35/mo
Unattributable
Other
Costly
Execution 455ms
Transfer 0 KB
Monthly Cost $9/mo
surveys-static-prd.survicate-cdn.com
Other
Costly
Execution 384ms
Transfer 160 KB
Unused 48%
Monthly Cost $7/mo
qb3mmcu0z3.kameleoon.io
Other
Costly
Execution 328ms
Transfer 43 KB
Monthly Cost $6/mo
Google Tag Manager
Tag Manager
Costly
Execution 301ms
Transfer 182 KB
Unused 39%
Monthly Cost $6/mo
cdn-files.dzcdn.net
Other
Optional
Execution 160ms
Transfer 113 KB
Unused 61%
Monthly Cost $3/mo
cdn-assets.dzcdn.net
Other
Optional
Execution 125ms
Transfer 0 KB
Monthly Cost $2/mo
Segment
Analytics
Optional
Execution 51ms
Transfer 9 KB
Monthly Cost $1/mo
Segment
Analytics
Optional
Execution 51ms
Transfer 22 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • Unattributable adds 455ms and costs ~$9/month
  • surveys-static-prd.survicate-cdn.com adds 384ms and costs ~$7/month
  • qb3mmcu0z3.kameleoon.io adds 328ms and costs ~$6/month
  • Google Tag Manager adds 301ms and costs ~$6/month

67% 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 455ms 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

surveys-static-prd.survicate-cdn.com takes 384ms 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

qb3mmcu0z3.kameleoon.io takes 328ms 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

Google Tag Manager takes 301ms 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

61% of cdn-files.dzcdn.net'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.

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