Performance
· 15 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.
605 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
892 ms
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
0 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.002
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
923 ms
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
892 ms
Page Load Progression
DHTTP CachingActionno-store (uncacheable)FIX
no-store, no-cache, must-revalidate, post-check=0, pre-check=0
| Directive | Value | Meaning |
|---|---|---|
| no-store | — | Never cache this response |
| no-cache | — | Cache but always revalidate first |
| must-revalidate | — | Must recheck with server after expiry |
| post-check | 0 | |
| pre-check | 0 |
BImage Optimization16 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
A+Page Weight Budget658 KB transferred, 50 requestsPASS
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
A+Third-Party Impact3% third-party, 0 ms blockingPASS
A+Text CompressionAll text resources are compressedPASS
A+JS Execution Cost262ms total JS executionPASS
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://proxmox.com/en/ | 145ms | 4ms | 1ms | 1st |
| Unattributable | 117ms | 7ms | 0ms | 3rd |
A+Font Loading4 fonts (384 KB)PASS
Web fonts
4
384 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Convert to woff2 for ~30% smaller file size
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
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)
Fixing the unchecked items could save ~170 KB and ~340 ms
A+JS Bundles17 scripts, 0 KB unusedPASS
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://proxmox.com/media/plg_n3tcookieconsent/js/n3tconsentmanager.js?f62601 | 5 KB | — | ✓ | 1st |
| https://proxmox.com/media/system/js/core.min.js?a3d8f8 | 4 KB | — | ✓ | 1st |
| https://proxmox.com/media/templates/site/cassiopeia/js/template.min.js?f62601 | 1 KB | — | ✓ | 1st |
| https://proxmox.com/media/vendor/bootstrap/js/offcanvas.min.js?5.3.8 | 2 KB | — | ✓ | 1st |
| https://proxmox.com/media/vendor/bootstrap/js/dropdown.min.js?5.3.8 | 3 KB | — | ✓ | 1st |
| https://proxmox.com/media/templates/site/cassiopeia_proxmox/js/user.js?f62601 | 1 KB | — | ✓ | 1st |
| https://proxmox.com/media/com_finder/js/finder.min.js?755761 | 1 KB | — | ✓ | 1st |
| https://proxmox.com/media/vendor/bootstrap/js/collapse.min.js?5.3.8 | 2 KB | — | ✓ | 1st |
| https://proxmox.com/media/system/js/fields/validate.min.js?75ac5d | 4 KB | — | ✓ | 1st |
| https://proxmox.com/media/system/js/messages.min.js?9a4811 | 2 KB | — | ✓ | 1st |
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Page Weight Inventory50 resources · 658 KB · 0 KB savings availablePASS
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 50 resources | 658.4 KiB | ||||||
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: firstcolo
Network Waterfall50 requests over 1435msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 117ms | 0 KB | — | £1/mo | Optional |
45% of JavaScript execution time comes from third-party scripts.
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