Performance
· 17 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.
3.89 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
19.80 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.09 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.
6.82 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.
20.00 s
Page Load Progression
FPage Weight BudgetAction3.6 MB transferred, 34 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS Execution CostAction2133ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.pubpub.org/dist/main.b5bf41f155d1784ec954.js | 844ms | 757ms | 84ms | 3rd |
| https://www.pubpub.org/ | 424ms | 22ms | 2ms | 3rd |
| https://www.pubpub.org/dist/vendor.53f35129c103d920c9ce.bundle.js | 367ms | 31ms | 318ms | 3rd |
| Unattributable | 299ms | 8ms | 0ms | 3rd |
| https://www.pubpub.org/cdn-cgi/challenge-platform/scripts/jsd/main.js | 199ms | 189ms | 2ms | 3rd |
FJS BundlesAction5 scripts, 938 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.pubpub.org/dist/vendor.53f35129c103d920c9ce.bundle.js | 1191 KB | 728 KB (61%) | ✓ | 3rd |
| https://www.pubpub.org/dist/main.b5bf41f155d1784ec954.js | 271 KB | 210 KB (78%) | ✓ | 3rd |
| https://polyfill-fastly.io/v3/polyfill.min.js?features=default,fetch,HTMLCanvasElement.prototype.toBlob,Node.prototype.contains,Array.prototype.find,Array.from,Number.isNaN,Object.assign,Object.entries,Object.values,Promise,requestIdleCallback,String.prototype.includes,URL,URLSearchParams | 0 KB | — | ✓ | 3rd |
| https://www.pubpub.org/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js | 1 KB | — | ✓ | 3rd |
| https://www.pubpub.org/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/main.js? | 12 KB | — | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction34 resources · 3.6 MB · 938 KB savings availableFIX
~937.9 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 34 resources | 3.6 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction17 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
A+Text CompressionAll text resources are compressedPASS
A+Font Loading1 fonts (32 KB)PASS
Web fonts
1
32 KB total
Render-blocking
0
of 1
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+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources 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 Waterfall34 requests over 1054msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.pubpub.org www.pubpub.org | Other | 844ms | 271 KB | 78% | $11/mo | Costly |
www.pubpub.org www.pubpub.org | Other | 424ms | 9 KB | — | $6/mo | Costly |
www.pubpub.org www.pubpub.org | Other | 367ms | 1191 KB | 61% | $5/mo | Costly |
Unattributable Unattributable | Other | 299ms | 0 KB | — | $4/mo | Costly |
www.pubpub.org www.pubpub.org | Other | 199ms | 0 KB | — | $3/mo | Optional |
These scripts may cost more than they're worth
- www.pubpub.org adds 844ms and costs ~$11/month
- www.pubpub.org adds 424ms and costs ~$6/month
- www.pubpub.org adds 367ms and costs ~$5/month
- Unattributable adds 299ms and costs ~$4/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
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
www.pubpub.org takes 844ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
78% of www.pubpub.org's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
www.pubpub.org takes 424ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.pubpub.org takes 367ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
61% of www.pubpub.org's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Unattributable takes 299ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev