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https://www.deezer.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
83
GRADE
B
FIX
3
REVIEW
4
PASS
7
INFO
2

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

Mobile Desktop
53
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.

6.68 s

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

11.17 s

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

286 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.

6.79 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.

11.20 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 4 REVIEW 3 FIX
D
Third-Party Impact
Action
83% third-party, 0 ms blocking
FIX
83% third-party, 0 ms blocking
Warning::
Third-party code accounts for 83% of page weight (1.2 MiB of 1.5 MiB)
Info::
Third-party blocking time is low (0 ms)
17%
83%
First-party Third-party
D
JS Execution Cost
Action
2134ms total JS execution
FIX
2134ms total JS execution
Warning::
https://www.deezer.com/CF6YEld6/91qK8Zv/WnnBwoW/9n...: 657ms CPU time
Warning::
https://surveys-static-prd.survicate-cdn.com/widge...: 333ms CPU time
Warning::
Unattributable: 326ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-PPQ...: 256ms CPU time
Info::
https://qb3mmcu0z3.kameleoon.io/engine.js: 243ms CPU time
Warning::
Third-party scripts: 1392ms (65% of total)

Main Thread Breakdown

Script Evaluation 64% Other 14% Script Parsing & Compilation 12% Style & Layout 7%
ScriptTotalScriptingParse/CompileParty
https://www.deezer.com/CF6YEld6/91qK8Zv/WnnBwoW/9n/E9kazL3Gwiu9Dp3Vb3/ChhnPnsWAg/TARDaxs2/DTsB657ms527ms40ms1st
https://surveys-static-prd.survicate-cdn.com/widget_core-28.22.7.js333ms209ms65ms3rd
Unattributable326ms55ms0ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-PPQNZ6256ms205ms49ms3rd
https://qb3mmcu0z3.kameleoon.io/engine.js243ms191ms14ms3rd
https://cdn-assets.dzcdn.net/common/js/gdpr-appliance.js137ms96ms40ms3rd
https://cdn-files.dzcdn.net/cache/js/app-backstage-plain-html.1de236d206f16f2e8525.js98ms64ms29ms3rd
https://www.deezer.com/us/85ms10ms2ms1st
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
Page Weight Budget
1.5 MB transferred, 52 requests
REVIEW
1.5 MB transferred, 52 requests
Info::
Page weighs 4.7 MB (1.5 MB transferred)
Warning::
JavaScript is 875 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 875 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 0.32 g CO2 per page load
1.5 MB / 2.4 MB budget
1.5 MB transferred
52 requests
0.32 g CO2 per page load
JavaScript 875.0 KiB 57%
Fonts 357.4 KiB 23%
Images 118.7 KiB 8%
Other 105.0 KiB 7%
HTML 51.0 KiB 3%
CSS 30.3 KiB 2%
Other 4.2 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

B
Image Optimization
8 images, 0 KB saveable
REVIEW
8 images, 0 KB saveable
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.
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.
8 images 119 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...: 39 KB unused (22%)
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.js112 KB68 KB (61%)✓3rd
https://www.deezer.com/CF6YEld6/91qK8Zv/WnnBwoW/9n/E9kazL3Gwiu9Dp3Vb3/ChhnPnsWAg/TARDaxs2/DTsB177 KB39 KB (22%)✓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.js3 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 FCP 6.7 s LCP 11.2 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
65% of JavaScript execution is third-party
First-party Third-party 1392ms · 498KB · $26/mo
surveys-static-prd.survicate-cdn.com
Other
Costly
Execution 333ms
Transfer 160 KB
Unused 48%
Monthly Cost $6/mo
Unattributable
Other
Costly
Execution 326ms
Transfer 0 KB
Monthly Cost $6/mo
Google Tag Manager
Tag Manager
Costly
Execution 256ms
Transfer 182 KB
Unused 39%
Monthly Cost $5/mo
qb3mmcu0z3.kameleoon.io
Other
Costly
Execution 243ms
Transfer 43 KB
Monthly Cost $5/mo
cdn-assets.dzcdn.net
Other
Optional
Execution 137ms
Transfer 0 KB
Monthly Cost $3/mo
cdn-files.dzcdn.net
Other
Optional
Execution 98ms
Transfer 112 KB
Unused 61%
Monthly Cost $2/mo

These scripts may cost more than they're worth

  • surveys-static-prd.survicate-cdn.com adds 333ms and costs ~$6/month
  • Unattributable adds 326ms and costs ~$6/month
  • Google Tag Manager adds 256ms and costs ~$5/month
  • qb3mmcu0z3.kameleoon.io adds 243ms and costs ~$5/month

65% 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

surveys-static-prd.survicate-cdn.com takes 333ms 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

Unattributable takes 326ms 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 256ms 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 243ms 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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