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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
78
GRADE
C
FIX
4
REVIEW
3
PASS
5
INFO
2

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

Mobile Desktop
33
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
98
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
69
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
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.

519 ms

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

2.86 s

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

694 ms

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

0.408

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

2.71 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.

4.41 s

Page Load Progression

887 ms
1.8 s
2.7 s
3.5 s
4.4 s
5.3 s
6.2 s
7.1 s
Checks
14
5 PASS 3 REVIEW 4 FIX
F
Page Weight Budget
Action
5.1 MB transferred, 262 requests
FIX
5.1 MB transferred, 262 requests
Critical::
Page weighs 12.2 MB (5.1 MB transferred)
Warning::
JavaScript is 2.2 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 2.2 MB
Warning::
262 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 1.1 g CO2 per page load
5.1 MB / 2.4 MB budget
5.1 MB transferred
262 requests
1.1 g CO2 per page load
JavaScript 2.2 MiB 44%
Other 1.9 MiB 37%
Images 569.2 KiB 11%
Other 241.9 KiB 5%
Fonts 120.7 KiB 2%
HTML 69.6 KiB 1%
CSS 18.6 KiB 0%
Other 3.2 KiB 0%
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

D
Third-Party Impact
Action
99% third-party, 0 ms blocking
FIX
99% third-party, 0 ms blocking
Warning::
Third-party code accounts for 99% of page weight (5.1 MiB of 5.1 MiB)
Info::
Third-party blocking time is low (0 ms)
99%
First-party Third-party
F
JS Execution Cost
Action
4059ms total JS execution
FIX
4059ms total JS execution
Warning::
https://assets.twitch.tv/assets/91539-59f35e010503...: 1715ms CPU time
Warning::
https://gql.twitch.tv/149e9513-01fa-4fb0-aad4-566a...: 446ms CPU time
Warning::
Unattributable: 405ms CPU time
Warning::
https://www.twitch.tv/: 399ms CPU time
Warning::
https://passport.twitch.tv/149e9513-01fa-4fb0-aad4...: 393ms CPU time
Warning::
Third-party scripts: 3660ms (90% of total)

Main Thread Breakdown

Script Evaluation 72% Other 11% Style & Layout 6% Script Parsing & Compilation 5%
ScriptTotalScriptingParse/CompileParty
https://assets.twitch.tv/assets/91539-59f35e010503504303ff.js1715ms1425ms22ms3rd
https://gql.twitch.tv/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/ips.js?KP_UIDZ_1=03aOJCGMQkbBrSvr5CtXmnDSHCYCcwqL1PwqFLMeeIxn34ZoD0weuvnq6rd83Zh6h7UxJkJIIi2oKIQoWZcRk7yN9KnTUFc7oXTqodgZROc9BbxgPFTpPQ9eFb4y901UlOrcEcllZgQIL8qAYA5v9STa862TkQDC4HULMgEnYzhcBYoiFm&x-kpsdk-v=j-1.2.308&x-kpsdk-im=AAKzafGK-xDLtKfpMceycE-D_hj1fyW5qi_6DZoNq0FISKD2f22mnu7hivmBZ0KL6eYsHuru_PpHMpcbN7EzAJSApt0446ms416ms8ms3rd
Unattributable405ms163ms0ms3rd
https://www.twitch.tv/399ms28ms5ms1st
https://passport.twitch.tv/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/ips.js?ga__15_abel=03h2lwaAMp9HNst9n1UO1tdxNVx3zijjbPRY1tSJSs3Tr78h2U8LK0bpTM57XKMmvSW3d3E3UtcvSMzcCDIlfMpBY0DiVrcWLPBQ9S17TzupgI8ddOJaVHQ3IoPBMt9OuUYWtjCxhUmvSRFRyaIYxZvruNRfW0YAAFw4fbb93DySpo8qVh&x-kpsdk-v=j-1.2.308&x-kpsdk-im=AAK_EacH8n-0yMR21TxG4dJmGvPP9_aKv9S7SWzwdQFTzO0DIz1nnVjSMivqa7_9MxxFaqanUwKen8JBhoeQqIRhzfo393ms345ms14ms3rd
https://assets.twitch.tv/assets/player-core-variant-b-976fc71ba01c6c79a34d.js263ms241ms6ms3rd
https://assets.twitch.tv/assets/core-ca9ab2f001b3e352d20f.js237ms218ms18ms3rd
https://k.twitchcdn.net/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/p.js139ms133ms4ms3rd
https://assets.twitch.tv/assets/59704-9ea106ccedc78a768443.js63ms49ms10ms3rd
D
JS Bundles
Action
133 scripts, 474 KB unused
FIX
133 scripts, 474 KB unused
Warning::
https://assets.twitch.tv/assets/core-ca9ab2f001b3e...: 91 KB unused (51%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://assets.twitch.tv/assets/core-ca9ab2f001b3e...: 91 KB unused (51%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://assets.twitch.tv/assets/91539-59f35e010503...: 77 KB unused (31%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://assets.twitch.tv/assets/59046-27942773076d...: 62 KB unused (45%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://assets.twitch.tv/assets/player-core-varian...: 56 KB unused (63%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 474 KB
474 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://assets.twitch.tv/assets/core-ca9ab2f001b3e352d20f.js0 KB91 KB (51%)✓3rd
https://assets.twitch.tv/assets/core-ca9ab2f001b3e352d20f.js180 KB91 KB (51%)✓3rd
https://assets.twitch.tv/assets/91539-59f35e010503504303ff.js249 KB77 KB (31%)✓3rd
https://assets.twitch.tv/assets/59046-27942773076d56d13e47.js137 KB62 KB (45%)✓3rd
https://assets.twitch.tv/assets/player-core-variant-b-976fc71ba01c6c79a34d.js88 KB56 KB (63%)✓3rd
https://assets.twitch.tv/assets/59704-9ea106ccedc78a768443.js124 KB28 KB (23%)✓3rd
https://assets.twitch.tv/assets/25470-7e6cf4529b483a2b8d52.js33 KB25 KB (77%)✓3rd
https://assets.twitch.tv/assets/features.whispers-b5bc585e9b0514283e17.js27 KB23 KB (88%)✓3rd
https://assets.twitch.tv/assets/88480-c2ad315a7fbaf96b5c8b.js24 KB21 KB (88%)✓3rd
https://assets.twitch.tv/assets/pages.front-ff3a227bccf7eda2812d.js18 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

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
Image Optimization
Action
42 images, 0 KB saveable
REVIEW
42 images, 0 KB saveable
Warning::
https://assets.twitch.tv/assets/cookie_pink-0c7a47... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://assets.twitch.tv/assets/An-AmazonCompanyBl... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
42 images 514 KB
0 oversized -0 KB
36 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
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

B
HTTP Caching
private, max-age=0
REVIEW
private, max-age=0
Info::
Cache-Control header is set
Got: private, max-age=0
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

private, max-age=0

DirectiveValueMeaning
private—Only browser cache, not CDN/proxy
max-age0Cache for 0 seconds
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
4 fonts (121 KB)
PASS
4 fonts (121 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

4

121 KB total

Render-blocking

0

of 4

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 FCP 519 ms LCP 2.9 shttps://assets.twitch.tv/assets/inter-latin-variable-wghtOnly-normal-a05a0d687a088c4efed3.woff2inter-latin-variable-wg... https://assets.twitch.tv/assets/inter-latin-variable-wghtOnly-normal-a05a0d687a088c4efed3.woff2 — 36.3 KiB — 0 ms — font-display: swaphttps://assets.twitch.tv/assets/Roobert-Medium-050c71a0449f34eb9cd3.woff2Roobert-Medium-050c71a0... https://assets.twitch.tv/assets/Roobert-Medium-050c71a0449f34eb9cd3.woff2 — 27.6 KiB — 0 ms — font-display: swaphttps://assets.twitch.tv/assets/Roobert-Regular-2b0345b049d46f67090f.woff2Roobert-Regular-2b0345b... https://assets.twitch.tv/assets/Roobert-Regular-2b0345b049d46f67090f.woff2 — 28.2 KiB — 0 ms — font-display: swaphttps://assets.twitch.tv/assets/Roobert-SemiBold-2c9de19c87721c9bcb39.woff2Roobert-SemiBold-2c9de1... https://assets.twitch.tv/assets/Roobert-SemiBold-2c9de19c87721c9bcb39.woff2 — 28.7 KiB — 0 ms — font-display: swap
inter-latin-variable-wg... woff2 swap
Size 36 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roobert-Medium-050c71a0... woff2 swap
Size 28 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roobert-Regular-2b0345b... woff2 swap
Size 28 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roobert-SemiBold-2c9de1... woff2 swap
Size 29 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
Network Waterfall
262 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
90% of JavaScript execution is third-party
First-party Third-party 3660ms · 998KB · $49/mo
assets.twitch.tv
Other
Costly
Execution 1715ms
Transfer 249 KB
Unused 31%
Monthly Cost $23/mo
gql.twitch.tv
Other
Costly
Execution 446ms
Transfer 234 KB
Monthly Cost $6/mo
Unattributable
Other
Costly
Execution 405ms
Transfer 0 KB
Monthly Cost $5/mo
passport.twitch.tv
Other
Costly
Execution 393ms
Transfer 246 KB
Monthly Cost $5/mo
assets.twitch.tv
Other
Costly
Execution 263ms
Transfer 88 KB
Unused 63%
Monthly Cost $3/mo
assets.twitch.tv
Other
Costly
Execution 237ms
Transfer 0 KB
Unused 51%
Monthly Cost $3/mo
k.twitchcdn.net
Other
Optional
Execution 139ms
Transfer 57 KB
Monthly Cost $2/mo
assets.twitch.tv
Other
Optional
Execution 63ms
Transfer 124 KB
Unused 23%
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • assets.twitch.tv adds 1715ms and costs ~$23/month
  • gql.twitch.tv adds 446ms and costs ~$6/month
  • Unattributable adds 405ms and costs ~$5/month
  • passport.twitch.tv adds 393ms and costs ~$5/month
  • assets.twitch.tv adds 263ms and costs ~$3/month
  • assets.twitch.tv adds 237ms and costs ~$3/month

90% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

assets.twitch.tv takes 1715ms 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

gql.twitch.tv takes 446ms 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 405ms 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

passport.twitch.tv takes 393ms 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

assets.twitch.tv takes 263ms 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

63% of assets.twitch.tv'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

assets.twitch.tv takes 237ms 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

51% of assets.twitch.tv'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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