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.
1.26 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.58 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
4 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.
1.71 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.
1.80 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CJS BundlesAction41 scripts, 192 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=GTM-KC3GXKG | 85 KB | 55 KB (65%) | ✓ | 3rd |
| https://connect.facebook.net/en_US/bundle/sdk.js/ | 78 KB | 54 KB (70%) | ✓ | 3rd |
| https://script.hotjar.com/modules.6a0f3932cb1341a35c18.js | 57 KB | 38 KB (67%) | ✓ | 3rd |
| https://www.couchsurfing.com/_next/static/chunks/1286-53c199d3d7e9bf7c.js | 45 KB | 24 KB (55%) | ✓ | 3rd |
| https://www.couchsurfing.com/_next/static/chunks/6472.979f65e4eacac81f.js | 45 KB | 20 KB (46%) | ✓ | 3rd |
| https://www.couchsurfing.com/_next/static/chunks/5357-fadf5353841e9502.js | 4 KB | — | ✓ | 3rd |
| https://www.couchsurfing.com/_next/static/chunks/7596-6a3a1cba7dc205b6.js | 32 KB | — | ✓ | 3rd |
| https://www.couchsurfing.com/_next/static/chunks/3124-dd1bc51ddd4546c7.js | 34 KB | — | ✓ | 3rd |
| https://www.couchsurfing.com/_next/static/chunks/7577-df79c9f1388ae97d.js | 43 KB | — | ✓ | 3rd |
| https://www.couchsurfing.com/_next/static/chunks/9692-be782428f85590cd.js | 3 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
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
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
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
APage Weight Budget845 KB transferred, 67 requestsPASS
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
A+Text CompressionAll text resources are compressedPASS
A+Image Optimization2 images, 0 KB saveablePASS
A+JS Execution Cost397ms total JS executionPASS
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.couchsurfing.com/_next/static/chunks/6233-4276772c5b8d0986.js | 171ms | 159ms | 3ms | 3rd |
| Unattributable | 87ms | 3ms | 0ms | 3rd |
| https://www.couchsurfing.com/welcome | 79ms | 3ms | 6ms | 3rd |
| https://www.couchsurfing.com/_next/static/chunks/7577-df79c9f1388ae97d.js | 60ms | 49ms | 5ms | 3rd |
A+Font Loading6 fonts (86 KB)PASS
Web fonts
6
86 KB total
Render-blocking
0
of 6
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
APage Weight Inventory67 resources · 845 KB · 192 KB savings availablePASS
~192.2 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 67 resources | 844.9 KiB | ||||||
Network Waterfall67 requests over 3981msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.couchsurfing.com www.couchsurfing.com | Other | 171ms | 32 KB | — | €2/mo | Optional |
Unattributable Unattributable | Other | 87ms | 0 KB | — | €1/mo | Optional |
www.couchsurfing.com www.couchsurfing.com | Other | 79ms | 37 KB | — | €1/mo | Optional |
www.couchsurfing.com www.couchsurfing.com | Other | 60ms | 43 KB | — | €1/mo | Optional |
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