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Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
80
GRADE
B
FIX
4
REVIEW
1
PASS
9
INFO
2

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

Mobile Desktop
51
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
99
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.

3.07 s

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

3.97 s

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

1.81 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.

4.91 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.

10.83 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
9 PASS 1 REVIEW 4 FIX
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 (1.8 MiB of 1.8 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
8724ms total JS execution
FIX
8724ms total JS execution
Warning::
https://bitwarden.com/: 3754ms CPU time
Warning::
https://bitwarden.com/build/assets/app-DDjafNz8.js: 2350ms CPU time
Warning::
Unattributable: 908ms CPU time
Warning::
https://cdn.ketchjs.com/ketchtag/stable/v2.12/ketc...: 584ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-NF3...: 561ms CPU time
Warning::
Third-party scripts: 8724ms (100% of total)

Main Thread Breakdown

Script Evaluation 37% Other 25% Style & Layout 17% Rendering 14% Parse HTML & CSS 3%
ScriptTotalScriptingParse/CompileParty
https://bitwarden.com/3754ms189ms2ms3rd
https://bitwarden.com/build/assets/app-DDjafNz8.js2350ms1785ms1ms3rd
Unattributable908ms203ms0ms3rd
https://cdn.ketchjs.com/ketchtag/stable/v2.12/ketch-sdk.js584ms395ms168ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-NF32QCS561ms446ms69ms3rd
https://bitwarden.com/build/assets/footer-DukkO7QU.js310ms107ms2ms3rd
https://bitwarden.com/plsbl/js/script.outbound-links.tagged-events.pageview-props.file-downloads.js181ms30ms1ms3rd
https://bitwarden.com/build/assets/page-wrapper-CuWZ0L4E.js75ms65ms1ms3rd
D
JS Bundles
Action
31 scripts, 406 KB unused
FIX
31 scripts, 406 KB unused
Warning::
https://cdn.ketchjs.com/ketchtag/stable/v2.12/ketc...: 117 KB unused (46%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://bitwarden.com/build/assets/footer-DukkO7QU...: 98 KB unused (62%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-NF3...: 80 KB unused (44%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://bitwarden.com/build/assets/app-DDjafNz8.js: 50 KB unused (47%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://bitwarden.com/build/assets/landing-page-CU...: 41 KB unused (54%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 406 KB
406 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://cdn.ketchjs.com/ketchtag/stable/v2.12/ketch-sdk.js257 KB117 KB (46%)✓3rd
https://bitwarden.com/build/assets/footer-DukkO7QU.js158 KB98 KB (62%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-NF32QCS180 KB80 KB (44%)✓3rd
https://bitwarden.com/build/assets/app-DDjafNz8.js105 KB50 KB (47%)✓3rd
https://bitwarden.com/build/assets/landing-page-CUBxvOJk.js77 KB41 KB (54%)✓3rd
https://bitwarden.com/build/assets/page-wrapper-CuWZ0L4E.js55 KB20 KB (37%)✓3rd
https://bitwarden.com/build/assets/article-list-card-BcZts8nl.js2 KB—✓3rd
https://bitwarden.com/build/assets/text-field-NSAZYs4U.js1 KB—✓3rd
https://bitwarden.com/build/assets/print-GrKw0ow3.js0 KB—✓3rd
https://bitwarden.com/build/assets/shield-loader-9YvpToAp.js0 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

F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Page Weight Budget
Action
1.8 MB transferred, 65 requests
REVIEW
1.8 MB transferred, 65 requests
Info::
Page weighs 6.9 MB (1.8 MB transferred)
Warning::
JavaScript is 1.2 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.2 MB
Info::
65 HTTP requests
Info::
Estimated 0.37 g CO2 per page load
1.8 MB / 2.4 MB budget
1.8 MB transferred
65 requests
0.37 g CO2 per page load
JavaScript 1.2 MiB 70%
Images 196.0 KiB 11%
Other 105.0 KiB 6%
HTML 103.9 KiB 6%
Fonts 84.5 KiB 5%
CSS 46.3 KiB 3%
Other 10.4 KiB 1%
Other 988 B 0%
Other 350 B 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

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
12 images, 0 KB saveable
PASS
12 images, 0 KB saveable
Info::
All images are well-optimized
12 images 196 KB
0 oversized -0 KB
1 legacy format
0 missing dimensions CLS risk
A+
Font Loading
2 fonts (85 KB)
PASS
2 fonts (85 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

85 KB total

Render-blocking

0

of 2

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 FCP 3.1 s LCP 4.0 shttps://cdn.jsdelivr.net/fontsource/fonts/inter:vf@latest/latin-wght-normal.woff2latin-wght-normal.woff2 https://cdn.jsdelivr.net/fontsource/fonts/inter:vf@latest/latin-wght-normal.woff2 — 47.6 KiB — 0 ms — font-display: swaphttps://bitwarden.com/build/assets/bwi-font-C46BVSvQ.woff2bwi-font-C46BVSvQ.woff2 https://bitwarden.com/build/assets/bwi-font-C46BVSvQ.woff2 — 36.9 KiB — 0 ms — font-display: swap
latin-wght-normal.woff2 woff2 swap
Size 48 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
bwi-font-C46BVSvQ.woff2 woff2 swap
Size 37 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
3 hints, 0 missing preconnects
PASS
3 hints, 0 missing preconnects
Info::
Page uses 3 resource hint(s)

Current Resource Hints

preconnect
—
preload
3
dns-prefetch
—
prefetch
—

3 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
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
65 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 8724ms · 862KB · $116/mo
bitwarden.com
Other
Costly
Execution 3754ms
Transfer 104 KB
Monthly Cost $50/mo
bitwarden.com
Other
Costly
Execution 2350ms
Transfer 105 KB
Unused 47%
Monthly Cost $31/mo
Unattributable
Other
Costly
Execution 908ms
Transfer 0 KB
Monthly Cost $12/mo
cdn.ketchjs.com
Other
Costly
Execution 584ms
Transfer 257 KB
Unused 46%
Monthly Cost $8/mo
Google Tag Manager
Tag Manager
Costly
Execution 561ms
Transfer 180 KB
Unused 44%
Monthly Cost $7/mo
bitwarden.com
Other
Costly
Execution 310ms
Transfer 158 KB
Unused 62%
Monthly Cost $4/mo
bitwarden.com
Other
Optional
Execution 181ms
Transfer 3 KB
Monthly Cost $2/mo
bitwarden.com
Other
Optional
Execution 75ms
Transfer 55 KB
Unused 37%
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • bitwarden.com adds 3754ms and costs ~$50/month
  • bitwarden.com adds 2350ms and costs ~$31/month
  • Unattributable adds 908ms and costs ~$12/month
  • cdn.ketchjs.com adds 584ms and costs ~$8/month
  • Google Tag Manager adds 561ms and costs ~$7/month
  • bitwarden.com adds 310ms and costs ~$4/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

bitwarden.com takes 3754ms 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

bitwarden.com takes 2350ms 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 908ms 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

cdn.ketchjs.com takes 584ms 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 561ms 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

bitwarden.com takes 310ms 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

62% of bitwarden.com'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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