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https://prettier.io

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
86
GRADE
B
FIX
0
REVIEW
4
PASS
8
INFO
2

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

Mobile Desktop
95
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
94
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.
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.

696 ms

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

1.44 s

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

32 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.

696 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

1.44 s

Page Load Progression

412 ms
824 ms
1.2 s
1.6 s
2.1 s
2.5 s
2.9 s
3.3 s
Checks
14
8 PASS 4 REVIEW
C
Image Optimization
Action
33 images, 0 KB saveable
REVIEW
33 images, 0 KB saveable
Warning::
https://prettier.io/images/github_grey.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/languages/tools_wip.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/users/used_by_facebook.... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/users/used_by_jest.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/users/used_by_react.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/languages/tools_css.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/languages/tools_yaml.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/languages/tools_md.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/users/used_by_storybook... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/languages/tools_html.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/syntaxfm/1.webp is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/users/used_by_babel.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/icon.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/users/used_by_yarn.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/users/dropbox_grey.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/users/used_by_danger.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://img.shields.io/github/stars/prettier/prett... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/state_of_js_grey.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/languages/tools_js.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/languages/tools_gql.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/users/used_by_webpack.s... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://prettier.io/images/npm_grey.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
33 images 144 KB
0 oversized -0 KB
29 legacy format
22 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

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

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

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

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

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

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

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

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

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

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

B
JS Execution Cost
767ms total JS execution
REVIEW
767ms total JS execution
Warning::
https://prettier.io/: 344ms CPU time
Info::
https://prettier.io/assets/js/main.977d5f67.js: 216ms CPU time
Info::
Unattributable: 134ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-T57C...: 73ms CPU time
Info::
Third-party scripts: 207ms (27% of total)

Main Thread Breakdown

Other 34% Script Evaluation 32% Style & Layout 16% Rendering 12% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://prettier.io/344ms3ms1ms1st
https://prettier.io/assets/js/main.977d5f67.js216ms174ms16ms1st
Unattributable134ms4ms0ms3rd
https://www.googletagmanager.com/gtag/js?id=G-T57CP1SG0273ms59ms13ms3rd
B
JS Bundles
32 scripts, 107 KB unused
REVIEW
32 scripts, 107 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-T57C...: 61 KB unused (42%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://prettier.io/assets/js/main.977d5f67.js: 46 KB unused (30%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 107 KB
107 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-T57CP1SG02145 KB61 KB (42%)✓3rd
https://prettier.io/assets/js/main.977d5f67.js154 KB46 KB (30%)✓1st
https://prettier.io/assets/js/3a21b1da.4942a829.js1 KB—✓1st
https://prettier.io/assets/js/06fcf392.95f141ad.js1 KB—✓1st
https://prettier.io/assets/js/9dd8a0d2.f8a43268.js3 KB—✓1st
https://prettier.io/assets/js/a7456010.f4e1b58d.js0 KB—✓1st
https://prettier.io/assets/js/5e95c892.6d0a09b0.js0 KB—✓1st
https://prettier.io/assets/js/aba21aa0.b5c62f24.js0 KB—✓1st
https://prettier.io/assets/js/a7bd4aaa.f262a25c.js1 KB—✓1st
https://prettier.io/assets/js/0058b4c6.cc1b2efc.js2 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

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

B
HTTP Caching
public,max-age=0,must-revalidate
REVIEW
public,max-age=0,must-revalidate
Info::
Cache-Control header is set
Got: public,max-age=0,must-revalidate
Info::
ETag present — enables conditional (304) responses
Cache-Control

public,max-age=0,must-revalidate

DirectiveValueMeaning
public—Any cache may store this response
max-age0Cache for 0 seconds
must-revalidate—Must recheck with server after expiry
A+
Page Weight Budget
565 KB transferred, 71 requests
PASS
565 KB transferred, 71 requests
Info::
Page weighs 1.4 MB (565 KB transferred)
Info::
71 HTTP requests
Info::
Estimated 0.12 g CO2 per page load
565 KB / 2.4 MB budget
565 KB transferred
71 requests
0.12 g CO2 per page load
JavaScript 340.9 KiB 60%
Images 144.2 KiB 26%
Other 42.0 KiB 7%
CSS 30.0 KiB 5%
HTML 6.8 KiB 1%
Other 546 B 0%
Other 546 B 0%
0 2.4 MB 4.9 MB
Under budget
A
Third-Party Impact
27% third-party, 0 ms blocking
PASS
27% third-party, 0 ms blocking
Info::
Third-party code accounts for 27% of page weight (153.2 KiB of 565.0 KiB)
Info::
Third-party blocking time is low (0 ms)
73%
27%
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+
Font Loading
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
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+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Google Cloud

Network Waterfall
71 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
27% of JavaScript execution is third-party
First-party Third-party 207ms · 145KB · $3/mo
Unattributable
Other
Optional
Execution 134ms
Transfer 0 KB
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 73ms
Transfer 145 KB
Unused 42%
Monthly Cost $1/mo

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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