Performance
· 27 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.62 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
4.34 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
5 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.004
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.62 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.
4.34 s
Page Load Progression
CImage OptimizationAction6 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
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.
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.
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.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
BJS Execution Cost665ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://e621.net/ | 356ms | 9ms | 3ms | 1st |
| Unattributable | 180ms | 8ms | 0ms | 3rd |
| https://e621.net/vite/assets/jquery-CocJsJE4.js | 129ms | 117ms | 1ms | 1st |
BHTTP/3 (QUIC)HTTP/3 not advertisedREVIEW
CCompression AlgorithmActionMain response served uncompressedREVIEW
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
BHTTP Cachingmax-age=0, private, must-revalidateREVIEW
max-age=0, private, must-revalidate
| Directive | Value | Meaning |
|---|---|---|
| max-age | 0 | Cache for 0 seconds |
| private | — | Only browser cache, not CDN/proxy |
| must-revalidate | — | Must recheck with server after expiry |
A+Page Weight Budget395 KB transferred, 35 requestsPASS
AThird-Party Impact29% third-party, 0 ms blockingPASS
A+Text CompressionAll text resources are compressedPASS
A+Font Loading2 fonts (132 KB)PASS
Web fonts
2
132 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
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+JS Bundles19 scripts, 0 KB unusedPASS
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://e621.net/vite/assets/application-CR0CteGZ.js | 4 KB | — | ✓ | 1st |
| https://e621.net/vite/assets/v_static_home-DRQpqNa8.js | 1 KB | — | ✓ | 1st |
| https://e621.net/vite/assets/jquery-CocJsJE4.js | 32 KB | — | ✓ | 1st |
| https://e621.net/vite/assets/rails-ujs.esm-BePOoTYg.js | 4 KB | — | ✓ | 1st |
| https://e621.net/vite/assets/autocomplete-CC0SGcah.js | 4 KB | — | ✓ | 1st |
| https://e621.net/vite/assets/DTextFormatter-DhLFn6IQ.js | 4 KB | — | ✓ | 1st |
| https://e621.net/vite/assets/PerformanceTracker-JSZuPS0L.js | 4 KB | — | ✓ | 1st |
| https://e621.net/vite/assets/User-BMCoaatC.js | 8 KB | — | ✓ | 1st |
| https://e621.net/vite/assets/Page-CShD7Rm3.js | 0 KB | — | ✓ | 1st |
| https://e621.net/vite/assets/hotkeys-cAhvnau0.js | 2 KB | — | ✓ | 1st |
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Main HTML Cache-ControlMain HTML max-age=0 (≤ 5min) is appropriatePASS
A+Server Response Intelligence1 server-response signal(s) detectedPASS
A+Page Weight Inventory35 resources · 395 KB · 0 KB savings availablePASS
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 35 resources | 394.5 KiB | ||||||
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
A+JavaScript BlockingNo render-blocking JS or document.write usage detectedPASS
A+CSS Performance DepthNo CSS performance depth issues detectedPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall35 requests over 1459msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 180ms | 0 KB | — | €2/mo | Optional |
Real-User Performance (CrUX)Field metrics from the Chrome User Experience ReportINFO
Chrome User Experience (CrUX)
Real-user metrics from the Chrome UX Report (2026-04-11 — 2026-05-08)
LCP (p75)
1423 ms
91% good
INP (p75)
97 ms
93% good
CLS (p75)
0.000
99% good
FCP (p75)
1052 ms
TTFB (p75)
717 ms
Image Optimization7 images, 5 KB total, 0 KB wastedINFO
Image Optimization Audit
Total Images
7
Total Size
5 KB