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https://prettier.io

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
86
GRADE
B
FIX
1
REVIEW
3
PASS
8
INFO
2

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

Mobile Desktop
62
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.

2.54 s

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

5.00 s

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

504 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.

4.98 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.

5.04 s

Page Load Progression

528 ms
1.1 s
1.6 s
2.1 s
2.6 s
3.2 s
3.7 s
4.2 s
Checks
14
8 PASS 3 REVIEW 1 FIX
D
JS Execution Cost
Action
2729ms total JS execution
FIX
2729ms total JS execution
Warning::
https://prettier.io/: 1118ms CPU time
Warning::
https://prettier.io/assets/js/main.977d5f67.js: 858ms CPU time
Warning::
Unattributable: 469ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-T57C...: 285ms CPU time
Info::
Third-party scripts: 754ms (28% of total)

Main Thread Breakdown

Script Evaluation 34% Other 32% Style & Layout 15% Rendering 13% Script Parsing & Compilation 5%
ScriptTotalScriptingParse/CompileParty
https://prettier.io/1118ms10ms3ms1st
https://prettier.io/assets/js/main.977d5f67.js858ms661ms63ms1st
Unattributable469ms11ms0ms3rd
https://www.googletagmanager.com/gtag/js?id=G-T57CP1SG02285ms225ms54ms3rd
C
Image Optimization
Action
33 images, 0 KB saveable
REVIEW
33 images, 0 KB saveable
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/github_grey.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/used_by_babel.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://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/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/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/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_storybook... 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.
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_css.svg 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/syntaxfm/1.webp 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/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/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/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_react.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
33 images 140 KB
0 oversized -0 KB
28 legacy format
21 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

B
JS Bundles
15 scripts, 106 KB unused
REVIEW
15 scripts, 106 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: 44 KB unused (29%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 106 KB
106 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 KB44 KB (29%)✓1st
https://prettier.io/assets/js/9dd8a0d2.f8a43268.js0 KB—✓1st
https://prettier.io/assets/js/9321.8cab51e7.js34 KB—✓1st
https://prettier.io/assets/js/9dd8a0d2.f8a43268.js2 KB—✓1st
https://prettier.io/assets/js/a7456010.f4e1b58d.js0 KB—✓1st
https://prettier.io/assets/js/runtime~main.96185ded.js5 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

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
538 KB transferred, 55 requests
PASS
538 KB transferred, 55 requests
Info::
Page weighs 1.4 MB (538 KB transferred)
Info::
55 HTTP requests
Info::
Estimated 0.11 g CO2 per page load
538 KB / 2.4 MB budget
538 KB transferred
55 requests
0.11 g CO2 per page load
JavaScript 340.9 KiB 63%
Images 141.9 KiB 26%
CSS 30.0 KiB 6%
Other 17.8 KiB 3%
HTML 6.8 KiB 1%
Other 555 B 0%
Other 546 B 0%
0 2.4 MB 4.9 MB
Under budget
A
Third-Party Impact
28% third-party, 0 ms blocking
PASS
28% third-party, 0 ms blocking
Info::
Third-party code accounts for 28% of page weight (150.8 KiB of 538.4 KiB)
Info::
Third-party blocking time is low (0 ms)
72%
28%
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
31 hints, 0 missing preconnects
PASS
31 hints, 0 missing preconnects
Info::
Page uses 31 resource hint(s)

Current Resource Hints

preconnect
2
preload
+19
29
dns-prefetch
—
prefetch
—

31 resource hints configured

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
55 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
28% of JavaScript execution is third-party
First-party Third-party 754ms · 145KB · $10/mo
Unattributable
Other
Costly
Execution 469ms
Transfer 0 KB
Monthly Cost $6/mo
Google Tag Manager
Tag Manager
Costly
Execution 285ms
Transfer 145 KB
Unused 42%
Monthly Cost $4/mo

These scripts may cost more than they're worth

  • Unattributable adds 469ms and costs ~$6/month
  • Google Tag Manager adds 285ms and costs ~$4/month

Unattributable takes 469ms 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 285ms 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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