Skip to content
https://news.ycombinator.com

Performance

· 25 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
94
GRADE
A
FIX
0
REVIEW
6
PASS
15
INFO
4

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

Mobile Desktop
100
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
52
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.
75
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.

864 ms

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

928 ms

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

14 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.

1.37 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.

928 ms

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
25
15 PASS 6 REVIEW
B
JS Execution Cost
501ms total JS execution
REVIEW
501ms total JS execution
Warning::
https://news.ycombinator.com/: 273ms CPU time
Info::
Unattributable: 228ms CPU time
Info::
Third-party scripts: 228ms (46% of total)

Main Thread Breakdown

Other 51% Style & Layout 28% Rendering 10% Script Evaluation 5% Parse HTML & CSS 5%
ScriptTotalScriptingParse/CompileParty
https://news.ycombinator.com/273ms7ms1ms1st
Unattributable228ms12ms0ms3rd
B
HTTP/3 (QUIC)
HTTP/3 not advertised
REVIEW
HTTP/3 not advertised
Info::
HTTP/3 (QUIC) is not advertised
HTTP/3 isn't advertised via Alt-Svc and the worker didn't negotiate h3. HTTP/3 reduces handshake latency (1-RTT instead of 2-3 RTTs) and is more resilient on lossy connections. Most modern CDNs (Cloudflare, Fastly, AWS CloudFront, Google Cloud CDN) support HTTP/3 with a single config switch -- consider enabling for mobile-heavy workloads.
C
Compression Algorithm
Action
Main response served uncompressed
REVIEW
Main response served uncompressed
Info::
Main HTML response has no Content-Encoding (uncompressed)
The main HTML document is served without compression. The Text Compression section above lists the broader picture; for the main response specifically, even gzip would shave ~70-80% off most text payloads.
B
Server-Timing Observability
No Server-Timing header found
REVIEW
No Server-Timing header found
Info::
No Server-Timing header found
Server-Timing exposes backend timing breakdowns to browser DevTools (e.g., `db: 45ms; render: 120ms; cache: 2ms`). Useful for diagnosing slow pages without backend log access. Most modern frameworks (Next.js, Cloudflare Workers, Fastly) emit it automatically; absence on a managed platform usually means telemetry headers are stripped at the edge.
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; max-age0
A+
Page Weight Budget
11 KB transferred, 7 requests
PASS
11 KB transferred, 7 requests
Info::
Page weighs 47 KB (11 KB transferred)
Info::
7 HTTP requests
Info::
Estimated 0.00 g CO2 per page load
11 KB / 2.4 MB budget
11 KB transferred
7 requests
0.00 g CO2 per page load
HTML 6.1 KiB 54%
JavaScript 2.1 KiB 19%
CSS 2.0 KiB 17%
Images 1.0 KiB 9%
Other 0 B 0%
0 2.4 MB 4.9 MB
Under budget
A+
Third-Party Impact
No third-party resources
PASS
No third-party resources
Info::
No third-party resources detected
No third-party resources detected — all resources are first-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
Image Optimization
3 images, 0 KB saveable
PASS
3 images, 0 KB saveable
Info::
All images are well-optimized
3 images 1 KB
0 oversized -0 KB
3 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+
JS Bundles
1 scripts, 0 KB unused
PASS
1 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://news.ycombinator.com/hn.js?XSk0rJr6l6WsiwmV3Oaq2 KB—✓1st
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+
LCP Image Preload
LCP preload audit not available
PASS
LCP preload audit not available
Info::
LCP image preload audit not available for this scan
A+
Main HTML Cache-Control
Main HTML max-age=0 (≤ 5min) is appropriate
PASS
Main HTML max-age=0 (≤ 5min) is appropriate
Info::
Main HTML max-age=0 (≤ 5min) is appropriate
Got: private; max-age=0
A+
Page Weight Inventory
7 resources · 11 KB · 0 KB savings available
PASS
7 resources · 11 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 11 KB
7 resources · 11.2 KiB · 0 third-party Within 1MB page-weight target
Document 54% · 6.1 KiB
JavaScript 19% · 2.1 KiB
CSS 17% · 2.0 KiB
Image 9% · 1.0 KiB
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
JavaScript Blocking
1 JS blocking issue(s) detected
PASS
1 JS blocking issue(s) detected
Warning::
1 render-blocking <script src> tag(s) without async/defer
Each `<script src=...>` without `async`, `defer`, or `type="module"` blocks HTML parsing while the browser fetches and executes it. The block lasts the entire round-trip + execution time -- on slow networks this translates directly into LCP delay. Add `defer` (executes after parse, in source order) for scripts that interact with the DOM, or `async` (executes whenever ready) for analytics / independent scripts. Module scripts (`type="module"`) are deferred by default.
Network Waterfall
7 requests over 806ms
INFO
0 ms 200 ms 400 ms 600 ms 800 ms FCP 864 ms LCP 928 mshttps://news.ycombinator.com// https://news.ycombinator.com/ — 200 — 6.1 KiB — 451 ms — h2https://news.ycombinator.com/news.css?XSk0rJr6l6WsiwmV3Oaq/news.css?XSk0rJr6l6WsiwmV3Oaq https://news.ycombinator.com/news.css?XSk0rJr6l6WsiwmV3Oaq — 200 — 2.0 KiB — 152 ms — h2https://news.ycombinator.com/y18.svg/y18.svg https://news.ycombinator.com/y18.svg — 200 — 511 B — 156 ms — h2https://news.ycombinator.com/hn.js?XSk0rJr6l6WsiwmV3Oaq/hn.js?XSk0rJr6l6WsiwmV3Oaq https://news.ycombinator.com/hn.js?XSk0rJr6l6WsiwmV3Oaq — 200 — 2.1 KiB — 153 ms — h2https://news.ycombinator.com/s.gif/s.gif https://news.ycombinator.com/s.gif — 200 — 233 B — 158 ms — h2https://news.ycombinator.com/triangle.svg/triangle.svg https://news.ycombinator.com/triangle.svg — 200 — 328 B — 151 ms — h2https://news.ycombinator.com/y18.svg/y18.svg https://news.ycombinator.com/y18.svg — 200 — 0 B — 5 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
46% of JavaScript execution is third-party
First-party Third-party 228ms · 0KB · $1/mo
Unattributable
Other
Costly
Execution 228ms
Transfer 0 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • Unattributable adds 228ms and costs ~$1/month

46% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

Unattributable takes 228ms 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

Real-User Performance (CrUX)
Field metrics from the Chrome User Experience Report
INFO

Chrome User Experience (CrUX)

Real-user metrics from the Chrome UX Report (2026-04-10 — 2026-05-07)

LCP (p75)

492 ms

99% good

INP (p75)

44 ms

100% good

CLS (p75)

0.000

100% good

FCP (p75)

494 ms

TTFB (p75)

570 ms

This origin passes Core Web Vitals assessment
Image Optimization
3 images, 0 KB total, 0 KB wasted
INFO

Image Optimization Audit

Total Images

3

Total Size

0 KB

3 missing alt text 2 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback