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https://www.twitch.tv

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
78
GRADE
C
FIX
3
REVIEW
4
PASS
7
INFO
2

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

Mobile Desktop
27
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
100
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
73
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.

6.45 s

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

8.49 s

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

4.23 s

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.

8.99 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.

17.77 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
Page Weight Budget
Action
2.4 MB transferred, 167 requests
FIX
2.4 MB transferred, 167 requests
Info::
Page weighs 5.3 MB (2.4 MB transferred)
Warning::
JavaScript is 1.3 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.3 MB
Warning::
167 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.51 g CO2 per page load
2.4 MB / 2.4 MB budget
2.4 MB transferred
167 requests
0.51 g CO2 per page load
JavaScript 1.3 MiB 52%
Images 927.4 KiB 37%
Fonts 177.1 KiB 7%
HTML 70.7 KiB 3%
Other 19.9 KiB 1%
CSS 3.9 KiB 0%
Other 3.6 KiB 0%
Other 2.2 KiB 0%
Other 1.3 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

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
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (2.4 MiB of 2.4 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
12644ms total JS execution
FIX
12644ms total JS execution
Warning::
https://assets.twitch.tv/assets/91539-59f35e010503...: 5324ms CPU time
Warning::
https://gql.twitch.tv/149e9513-01fa-4fb0-aad4-566a...: 2104ms CPU time
Warning::
https://passport.twitch.tv/149e9513-01fa-4fb0-aad4...: 2099ms CPU time
Warning::
Unattributable: 1041ms CPU time
Warning::
https://m.twitch.tv/?desktop-redirect=true: 664ms CPU time
Warning::
Third-party scripts: 12644ms (100% of total)

Main Thread Breakdown

Script Evaluation 76% Other 10% Style & Layout 6% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://assets.twitch.tv/assets/91539-59f35e010503504303ff.js5324ms4531ms92ms3rd
https://gql.twitch.tv/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/ips.js?KP_UIDZ_1=03M15dhp2uTsrXr6SadVu9Lw5aagOLv1fguBEwrICRaXX85eJv5N0xxTB0FZXajXar6SbCSy3htzvQsKLLpy6X5VqhTeDNWWTKlMMohL53OyqKRPVYcdttwqhWcvesIkho8cdR3B6aUaVBQGSeqxYJ9npo0dn1d9cBJODwRcdsFE8G3P8G&x-kpsdk-v=j-1.2.308&x-kpsdk-im=AAKp0YUOaAqmGfhfyZvyYhiZAoBuJ1s1ZajydG0alhtUa5hb_Ts7NJlDoYIh54tXuhZzWKSgdz-MbWbTc96-q1KdYe42104ms1911ms55ms3rd
https://passport.twitch.tv/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/ips.js?ga__15_abel=03szbylzzMfw70YsxHmVL6XuTGSGPAVh8HjHQflHAUcyWop7hOo7TdEyqKDbQtJFsdihkjR56avMEZNWbk17lBVQdYToHaqk6iTdCL3mhJX5j0VKpkbmWFUyN2suUfFIxS3XCSsk2lmDxRW3AzLw4HhWKbkqBaKkRpFju01MsI6noOPy61&x-kpsdk-v=j-1.2.308&x-kpsdk-im=AALJ8w0o6hab6AjmkZlDavvaWzC5OrhuZvaZsaDHfm1IW91GaLIcVNIEH-SCZY5WznE9gVg6fL9LIgIJ4JbIC58Jvwk2099ms1963ms40ms3rd
Unattributable1041ms144ms1ms3rd
https://m.twitch.tv/?desktop-redirect=true664ms89ms18ms3rd
https://assets.twitch.tv/assets/mweb-main-7586ffd494cd6cfdb5b3.js535ms530ms5ms3rd
https://k.twitchcdn.net/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/p.js486ms449ms30ms3rd
https://assets.twitch.tv/assets/59704-9ea106ccedc78a768443.js168ms114ms43ms3rd
https://assets.twitch.tv/assets/46986-1961ac3c50fade2bc71f.js138ms16ms1ms3rd
https://assets.twitch.tv/assets/flags-fbdca44fe6fad210a8c6.js86ms1ms75ms3rd
B
Image Optimization
89 images, 0 KB saveable
REVIEW
89 images, 0 KB saveable
Warning::
https://static-cdn.jtvnw.net/twilight-static-asset... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
89 images 927 KB
0 oversized -0 KB
88 legacy format
1 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

C
JS Bundles
Action
43 scripts, 157 KB unused
REVIEW
43 scripts, 157 KB unused
Warning::
https://assets.twitch.tv/assets/91539-59f35e010503...: 86 KB unused (34%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://assets.twitch.tv/assets/flags-fbdca44fe6fa...: 39 KB unused (66%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://assets.twitch.tv/assets/59704-9ea106ccedc7...: 33 KB unused (27%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 157 KB
157 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://assets.twitch.tv/assets/91539-59f35e010503504303ff.js249 KB86 KB (34%)✓3rd
https://assets.twitch.tv/assets/flags-fbdca44fe6fad210a8c6.js58 KB39 KB (66%)✓3rd
https://assets.twitch.tv/assets/59704-9ea106ccedc78a768443.js124 KB33 KB (27%)✓3rd
https://assets.twitch.tv/assets/10530-8a68c3f1db9efc715645.js10 KB—✓3rd
https://assets.twitch.tv/assets/64967-c4cc6b3cf3d36ee3db8b.js17 KB—✓3rd
https://assets.twitch.tv/assets/71259-3bcd239c1a3eccc7843e.js8 KB—✓3rd
https://assets.twitch.tv/assets/79004-adee6b9b24e5f508c5ba.js7 KB—✓3rd
https://assets.twitch.tv/assets/79058-307ba85d09ac48f03d14.js3 KB—✓3rd
https://assets.twitch.tv/assets/80399-4bb68412b634fa76378e.js7 KB—✓3rd
https://assets.twitch.tv/assets/22367-63138a15797201b78256.js5 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

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
5 fonts (177 KB)
PASS
5 fonts (177 KB)
Info::
5 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

5

177 KB total

Render-blocking

0

of 5

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 6.0 s 7.0 s 8.0 s FCP 6.5 s LCP 8.5 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-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-Medium-050c71a0449f34eb9cd3.woff2Roobert-Medium-050c71a0... https://assets.twitch.tv/assets/Roobert-Medium-050c71a0449f34eb9cd3.woff2 — 27.2 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: swaphttps://assets.twitch.tv/assets/inter-latin-ext-variable-wghtOnly-normal-29df4aa934ecc9462070.woff2inter-latin-ext-variabl... https://assets.twitch.tv/assets/inter-latin-ext-variable-wghtOnly-normal-29df4aa934ecc9462070.woff2 — 56.7 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-Regular-2b0345b... woff2 swap
Size 28 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roobert-Medium-050c71a0... woff2 swap
Size 27 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
inter-latin-ext-variabl... woff2 swap
Size 57 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
11 hints, 0 missing preconnects
PASS
11 hints, 0 missing preconnects
Info::
Page uses 11 resource hint(s)

Current Resource Hints

preconnect
3
preload
2
dns-prefetch
6
prefetch
—

11 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
167 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
100% of JavaScript execution is third-party
First-party Third-party 12644ms · 1069KB · $168/mo
assets.twitch.tv
Other
Costly
Execution 5324ms
Transfer 249 KB
Unused 34%
Monthly Cost $71/mo
gql.twitch.tv
Other
Costly
Execution 2104ms
Transfer 244 KB
Monthly Cost $28/mo
passport.twitch.tv
Other
Costly
Execution 2099ms
Transfer 246 KB
Monthly Cost $28/mo
Unattributable
Other
Costly
Execution 1041ms
Transfer 0 KB
Monthly Cost $14/mo
m.twitch.tv
Other
Costly
Execution 664ms
Transfer 67 KB
Monthly Cost $9/mo
assets.twitch.tv
Other
Costly
Execution 535ms
Transfer 18 KB
Monthly Cost $7/mo
k.twitchcdn.net
Other
Costly
Execution 486ms
Transfer 56 KB
Monthly Cost $6/mo
assets.twitch.tv
Other
Optional
Execution 168ms
Transfer 124 KB
Unused 27%
Monthly Cost $2/mo
assets.twitch.tv
Other
Optional
Execution 138ms
Transfer 6 KB
Monthly Cost $2/mo
assets.twitch.tv
Other
Optional
Execution 86ms
Transfer 58 KB
Unused 66%
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • assets.twitch.tv adds 5324ms and costs ~$71/month
  • gql.twitch.tv adds 2104ms and costs ~$28/month
  • passport.twitch.tv adds 2099ms and costs ~$28/month
  • Unattributable adds 1041ms and costs ~$14/month
  • m.twitch.tv adds 664ms and costs ~$9/month
  • assets.twitch.tv adds 535ms and costs ~$7/month
  • k.twitchcdn.net adds 486ms and costs ~$6/month

100% 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 5324ms 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 2104ms 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 2099ms 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 1041ms 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

m.twitch.tv takes 664ms 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 535ms 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

k.twitchcdn.net takes 486ms 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

66% 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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