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https://deepseek.com

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
96
GRADE
A
FIX
0
REVIEW
2
PASS
13
INFO
2

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

Mobile Desktop
75
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
96
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.
91
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.

1.13 s

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

5.28 s

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

269 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.

1.49 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.

5.28 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
17
13 PASS 2 REVIEW
C
JS Execution Cost
Action
1742ms total JS execution
REVIEW
1742ms total JS execution
Warning::
https://deepseek.com/: 768ms CPU time
Warning::
https://deepseek.com/_next/static/chunks/6714-6422...: 406ms CPU time
Info::
Unattributable: 214ms CPU time
Info::
https://deepseek.com/_next/static/chunks/8848-d252...: 162ms CPU time
Info::
https://deepseek.com/_next/static/chunks/c56f180e-...: 136ms CPU time
Info::
Third-party scripts: 214ms (12% of total)

Main Thread Breakdown

Script Evaluation 38% Style & Layout 35% Other 16% Script Parsing & Compilation 8%
ScriptTotalScriptingParse/CompileParty
https://deepseek.com/768ms16ms21ms1st
https://deepseek.com/_next/static/chunks/6714-6422be53e1640400.js406ms374ms19ms1st
Unattributable214ms8ms0ms3rd
https://deepseek.com/_next/static/chunks/8848-d252791ce07a3fe3.js162ms135ms26ms1st
https://deepseek.com/_next/static/chunks/c56f180e-6001d5763de6082d.js136ms102ms28ms1st
https://deepseek.com/_next/static/chunks/5069-6affb9693b43a1d0.js55ms35ms19ms1st
B
HTTP Caching
no-cache
REVIEW
no-cache
Info::
Cache-Control header is set
Got: no-cache
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present
Cache-Control

no-cache

DirectiveValueMeaning
no-cache—Cache but always revalidate first
A+
Page Weight Budget
566 KB transferred, 18 requests
PASS
566 KB transferred, 18 requests
Info::
Page weighs 1.1 MB (566 KB transferred)
Info::
18 HTTP requests
Info::
Estimated 0.12 g CO2 per page load
566 KB / 2.4 MB budget
566 KB transferred
18 requests
0.12 g CO2 per page load
JavaScript 230.8 KiB 41%
Other 205.4 KiB 36%
Fonts 47.7 KiB 8%
Images 46.6 KiB 8%
HTML 20.8 KiB 4%
CSS 14.0 KiB 2%
Other 539 B 0%
0 2.4 MB 4.9 MB
Under budget
A+
Third-Party Impact
8% third-party, 0 ms blocking
PASS
8% third-party, 0 ms blocking
Info::
Third-party code accounts for 8% of page weight (47.1 KiB of 565.8 KiB)
Info::
Third-party blocking time is low (0 ms)
92%
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
Image Optimization
2 images, 0 KB saveable
PASS
2 images, 0 KB saveable
Info::
All images are well-optimized
2 images 47 KB
0 oversized -0 KB
2 legacy format
0 missing dimensions CLS risk
A+
Font Loading
1 fonts (48 KB)
PASS
1 fonts (48 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

48 KB total

Render-blocking

0

of 1

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 1.1 s LCP 5.3 shttps://deepseek.com/_next/static/media/e4af272ccee01ff0-s.p.woff2e4af272ccee01ff0-s.p.woff2 https://deepseek.com/_next/static/media/e4af272ccee01ff0-s.p.woff2 — 47.7 KiB — 19 ms — font-display: swap
e4af272ccee01ff0-s.p.woff2 woff2 swap
Size 48 KB
Load time 19 ms
Start 39 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+
JS Bundles
9 scripts, 34 KB unused
PASS
9 scripts, 34 KB unused
Warning::
https://deepseek.com/_next/static/chunks/8848-d252...: 34 KB unused (61%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 34 KB
34 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://deepseek.com/_next/static/chunks/8848-d252791ce07a3fe3.js56 KB34 KB (61%)✓1st
https://deepseek.com/_next/static/chunks/webpack-2e06bec4baf15881.js6 KB—✓1st
https://deepseek.com/_next/static/chunks/c56f180e-6001d5763de6082d.js54 KB—✓1st
https://deepseek.com/_next/static/chunks/6714-6422be53e1640400.js29 KB—✓1st
https://deepseek.com/_next/static/chunks/main-app-0138e63140c237ca.js1 KB—✓1st
https://deepseek.com/_next/static/chunks/2278-6827556f92234ddf.js28 KB—✓1st
https://deepseek.com/_next/static/chunks/app/%5Blocale%5D/layout-761353d13bda8476.js2 KB—✓1st
https://deepseek.com/_next/static/chunks/5069-6affb9693b43a1d0.js31 KB—✓1st
https://deepseek.com/_next/static/chunks/app/%5Blocale%5D/page-a8799f32b82d85c2.js23 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

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+
Page Weight Inventory
18 resources · 566 KB · 34 KB savings available
PASS
18 resources · 566 KB · 34 KB savings available
Info::
Within 1MB page-weight target
Got: 566 KB
Info::
3 third-party resources (8% of weight)
Info::
1 resources over 200KB
18 resources · 565.8 KiB · 3 third-party Within 1MB page-weight target
Image 45% · 252.0 KiB
JavaScript 41% · 230.8 KiB
Font 8% · 47.7 KiB
Document 4% · 20.8 KiB
CSS 2% · 14.0 KiB
Other 0% · 539 B

~34.1 KiB of savings available

Remove unused JavaScript: 34.1 KiB
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
18 requests over 810ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 1.1 s LCP 5.3 shttps://deepseek.com// https://deepseek.com/ — 200 — 20.8 KiB — 18 ms — h2https://deepseek.com/_next/static/media/e4af272ccee01ff0-s.p.woff2/_next/static/media/e4af272ccee01ff... https://deepseek.com/_next/static/media/e4af272ccee01ff0-s.p.woff2 — 200 — 47.7 KiB — 19 ms — h2https://deepseek.com/_next/static/css/4ed2fe305fed57cc.css/_next/static/css/4ed2fe305fed57cc.... https://deepseek.com/_next/static/css/4ed2fe305fed57cc.css — 200 — 7.5 KiB — 8 ms — h2https://deepseek.com/_next/static/css/b794593e5feb2b94.css/_next/static/css/b794593e5feb2b94.... https://deepseek.com/_next/static/css/b794593e5feb2b94.css — 200 — 4.5 KiB — 11 ms — h2https://deepseek.com/_next/static/css/2cbd522464c80da0.css/_next/static/css/2cbd522464c80da0.... https://deepseek.com/_next/static/css/2cbd522464c80da0.css — 200 — 2.0 KiB — 14 ms — h2https://deepseek.com/_next/static/chunks/webpack-2e06bec4baf15881.js/_next/static/chunks/webpack-2e06be... https://deepseek.com/_next/static/chunks/webpack-2e06bec4baf15881.js — 200 — 5.8 KiB — 10 ms — h2https://deepseek.com/_next/static/chunks/c56f180e-6001d5763de6082d.js/_next/static/chunks/c56f180e-6001d... https://deepseek.com/_next/static/chunks/c56f180e-6001d5763de6082d.js — 200 — 53.8 KiB — 49 ms — h2https://deepseek.com/_next/static/chunks/6714-6422be53e1640400.js/_next/static/chunks/6714-6422be53e... https://deepseek.com/_next/static/chunks/6714-6422be53e1640400.js — 200 — 29.2 KiB — 30 ms — h2https://deepseek.com/_next/static/chunks/main-app-0138e63140c237ca.js/_next/static/chunks/main-app-0138e... https://deepseek.com/_next/static/chunks/main-app-0138e63140c237ca.js — 200 — 816 B — 21 ms — h2https://deepseek.com/_next/static/chunks/8848-d252791ce07a3fe3.js/_next/static/chunks/8848-d252791ce... https://deepseek.com/_next/static/chunks/8848-d252791ce07a3fe3.js — 200 — 56.2 KiB — 47 ms — h2https://deepseek.com/_next/static/chunks/2278-6827556f92234ddf.js/_next/static/chunks/2278-6827556f9... https://deepseek.com/_next/static/chunks/2278-6827556f92234ddf.js — 200 — 28.4 KiB — 47 ms — h2https://deepseek.com/_next/static/chunks/app/%5Blocale%5D/layout-761353d13bda8476.js/_next/static/chunks/app/%5Blocale%... https://deepseek.com/_next/static/chunks/app/%5Blocale%5D/layout-761353d13bda8476.js — 200 — 2.2 KiB — 32 ms — h2https://deepseek.com/_next/static/chunks/5069-6affb9693b43a1d0.js/_next/static/chunks/5069-6affb9693... https://deepseek.com/_next/static/chunks/5069-6affb9693b43a1d0.js — 200 — 31.3 KiB — 49 ms — h2https://deepseek.com/_next/static/chunks/app/%5Blocale%5D/page-a8799f32b82d85c2.js/_next/static/chunks/app/%5Blocale%... https://deepseek.com/_next/static/chunks/app/%5Blocale%5D/page-a8799f32b82d85c2.js — 200 — 23.2 KiB — 44 ms — h2https://cdn.deepseek.com/blog/banner-background.webpcdn.deepseek.com/blog/banner-backgr... https://cdn.deepseek.com/blog/banner-background.webp — 200 — 37.4 KiB — 696 ms — h2https://cdn.deepseek.com/logo.png?x-image-process=image%2Fresize%2Cw_1920cdn.deepseek.com/logo.png?x-image-p... https://cdn.deepseek.com/logo.png?x-image-process=image%2Fresize%2Cw_1920 — 200 — 9.2 KiB — 397 ms — h2https://chat.deepseek.com/api/v0/ip_to_country_codechat.deepseek.com/api/v0/ip_to_coun... https://chat.deepseek.com/api/v0/ip_to_country_code — 200 — 539 B — 271 ms — h2https://deepseek.com/favicon.ico/favicon.ico https://deepseek.com/favicon.ico — 200 — 205.4 KiB — 15 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
12% of JavaScript execution is third-party
First-party Third-party 214ms · 0KB · $3/mo
Unattributable
Other
Costly
Execution 214ms
Transfer 0 KB
Monthly Cost $3/mo

These scripts may cost more than they're worth

  • Unattributable adds 214ms and costs ~$3/month

Unattributable takes 214ms 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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