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https://www.unsplash.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
83
GRADE
B
FIX
3
REVIEW
3
PASS
8
INFO
2

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

Mobile Desktop
80
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
90
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
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.

2.12 s

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

2.49 s

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

596 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.

2.12 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.

9.03 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
8 PASS 3 REVIEW 3 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 (1.4 MiB of 1.4 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
3747ms total JS execution
FIX
3747ms total JS execution
Warning::
https://unsplash.com/a/en-US/lib-react.2637b5c2.js: 1701ms CPU time
Warning::
https://unsplash.com/: 657ms CPU time
Warning::
https://unsplash.com/a/en-US/main.06edf429.js: 649ms CPU time
Warning::
Unattributable: 582ms CPU time
Info::
https://unsplash.com/a/en-US/6990.1c294f34.js: 85ms CPU time
Warning::
Third-party scripts: 3747ms (100% of total)

Main Thread Breakdown

Script Evaluation 62% Other 16% Script Parsing & Compilation 6% Style & Layout 6% Rendering 3%
ScriptTotalScriptingParse/CompileParty
https://unsplash.com/a/en-US/lib-react.2637b5c2.js1701ms1637ms15ms3rd
https://unsplash.com/657ms41ms26ms3rd
https://unsplash.com/a/en-US/main.06edf429.js649ms595ms43ms3rd
Unattributable582ms11ms0ms3rd
https://unsplash.com/a/en-US/6990.1c294f34.js85ms35ms36ms3rd
https://unsplash.com/a/en-US/async/asset-route.38de6b5a.js72ms62ms9ms3rd
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.

B
Page Weight Budget
1.4 MB transferred, 80 requests
REVIEW
1.4 MB transferred, 80 requests
Info::
Page weighs 3.5 MB (1.4 MB transferred)
Warning::
JavaScript is 644 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 644 KB
Info::
80 HTTP requests
Info::
Estimated 0.29 g CO2 per page load
1.4 MB / 2.4 MB budget
1.4 MB transferred
80 requests
0.29 g CO2 per page load
Images 649.9 KiB 46%
JavaScript 643.7 KiB 46%
HTML 92.2 KiB 7%
Other 9.1 KiB 1%
CSS 7.4 KiB 1%
Other 1.9 KiB 0%
Other 1008 B 0%
Other 0 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Under 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

C
JS Bundles
Action
21 scripts, 222 KB unused
REVIEW
21 scripts, 222 KB unused
Warning::
https://unsplash.com/a/en-US/main.06edf429.js: 85 KB unused (61%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://unsplash.com/a/en-US/6990.1c294f34.js: 65 KB unused (51%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://unsplash.com/a/en-US/4142.9b883bb0.js: 51 KB unused (43%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://unsplash.com/a/en-US/async/asset-route.38d...: 21 KB unused (90%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 222 KB
222 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://unsplash.com/a/en-US/main.06edf429.js139 KB85 KB (61%)✓3rd
https://unsplash.com/a/en-US/6990.1c294f34.js129 KB65 KB (51%)✓3rd
https://unsplash.com/a/en-US/4142.9b883bb0.js119 KB51 KB (43%)✓3rd
https://unsplash.com/a/en-US/async/asset-route.38de6b5a.js24 KB21 KB (90%)✓3rd
https://unsplash.com/a/en-US/async/1043.146ae9c1.js18 KB—✓3rd
https://unsplash.com/a/en-US/async/1798.e2669368.js5 KB—✓3rd
https://unsplash.com/a/en-US/async/498.c107f79e.js4 KB—✓3rd
https://unsplash.com/a/en-US/async/4692.153f2955.js4 KB—✓3rd
https://unsplash.com/a/en-US/async/6052.b4d378d2.js26 KB—✓3rd
https://unsplash.com/a/en-US/async/featured-photos-feed-route.337f674a.js3 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

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

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
44 images, 0 KB saveable
PASS
44 images, 0 KB saveable
Info::
All images are well-optimized
44 images 650 KB
0 oversized -0 KB
1 legacy format
0 missing dimensions CLS risk
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+
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
80 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 3747ms · 435KB · $50/mo
unsplash.com
Other
Costly
Execution 1701ms
Transfer 55 KB
Monthly Cost $23/mo
unsplash.com
Other
Costly
Execution 657ms
Transfer 89 KB
Monthly Cost $9/mo
unsplash.com
Other
Costly
Execution 649ms
Transfer 139 KB
Unused 61%
Monthly Cost $9/mo
Unattributable
Other
Costly
Execution 582ms
Transfer 0 KB
Monthly Cost $8/mo
unsplash.com
Other
Optional
Execution 85ms
Transfer 129 KB
Unused 51%
Monthly Cost $1/mo
unsplash.com
Other
Optional
Execution 72ms
Transfer 24 KB
Unused 90%
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • unsplash.com adds 1701ms and costs ~$23/month
  • unsplash.com adds 657ms and costs ~$9/month
  • unsplash.com adds 649ms and costs ~$9/month
  • Unattributable adds 582ms and costs ~$8/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

unsplash.com takes 1701ms 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

unsplash.com takes 657ms 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

unsplash.com takes 649ms 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

61% of unsplash.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

Unattributable takes 582ms 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 unsplash.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

90% of unsplash.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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