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.
11.31 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
32.71 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.40 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.
14.59 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.
33.40 s
Page Load Progression
FPage Weight BudgetAction5.5 MB transferred, 83 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
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
DThird-Party ImpactAction89% third-party, 0 ms blockingFIX
FJS Execution CostAction4864ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 977ms | 663ms | 260ms | 3rd |
| Unattributable | 752ms | 149ms | 0ms | 3rd |
| https://jacobin.com/ | 433ms | 25ms | 2ms | 1st |
| https://cdn.fuseplatform.net/publift/tags/2/4027/fuse.js | 419ms | 353ms | 37ms | 3rd |
| https://geo.cookie-script.com/s/dd3762a1df8013cbdfaf7dc8e7aecf42.js?country=gb®ion=eu | 346ms | 222ms | 10ms | 3rd |
| https://js.stripe.com/v3/ | 288ms | 162ms | 125ms | 3rd |
| https://cdn.fuseplatform.net/prebid/prebid-9.53.5-59b3f3e472d57a74bd2465fd9536b601.js | 254ms | 216ms | 36ms | 3rd |
| https://jacobin.com/static/1776722461/js/jacobin.js | 233ms | 183ms | 49ms | 1st |
| https://www.googletagmanager.com/gtag/js?id=G-52MH01NGXV&cx=c>m=4e64k0 | 211ms | 168ms | 42ms | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604170101/pubads_impl.js?cb=31097963 | 202ms | 156ms | 40ms | 3rd |
Showing top 10 of 16 scripts
FJS BundlesAction29 scripts, 1.3 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 0 KB | 177 KB (49%) | ✓ | 3rd |
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 362 KB | 177 KB (49%) | ✓ | 3rd |
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 362 KB | 177 KB (49%) | ✓ | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604170101/pubads_impl.js?cb=31097963 | 187 KB | 132 KB (71%) | ✓ | 3rd |
| https://js.stripe.com/v3/ | 221 KB | 132 KB (73%) | ✓ | 3rd |
| https://cdn.fuseplatform.net/prebid/prebid-9.53.5-59b3f3e472d57a74bd2465fd9536b601.js | 148 KB | 114 KB (77%) | ✓ | 3rd |
| https://jacobin.com/static/1776722461/js/jacobin.js | 157 KB | 106 KB (68%) | ✓ | 1st |
| https://cmp.inmobi.com/tcfv2/56/cmp2.js?referer=jacobin.com | 112 KB | 75 KB (67%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-52MH01NGXV&cx=c>m=4e64k0 | 164 KB | 67 KB (41%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-5GCNZ33N | 145 KB | 65 KB (45%) | ✓ | 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
FPage Weight InventoryAction83 resources · 5.5 MB · 1.3 MB savings availableFIX
~1.3 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 83 resources | 5.5 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction23 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
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
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
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 Loading9 fonts (408 KB)PASS
Web fonts
9
408 KB total
Render-blocking
0
of 9
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
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 ~77 KB and ~154 ms
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 Waterfall83 requests over 2863msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.gstatic.com www.gstatic.com | Other | 977ms | 0 KB | 49% | $13/mo | Costly |
Unattributable Unattributable | Other | 752ms | 0 KB | — | $10/mo | Costly |
cdn.fuseplatform.net cdn.fuseplatform.net | Other | 419ms | 102 KB | 42% | $6/mo | Costly |
geo.cookie-script.com geo.cookie-script.com | Other | 346ms | 25 KB | — | $5/mo | Costly |
Stripe js.stripe.com | Payment | 288ms | 221 KB | 73% | $4/mo | Essential |
cdn.fuseplatform.net cdn.fuseplatform.net | Other | 254ms | 148 KB | 77% | $3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 211ms | 164 KB | 41% | $3/mo | Costly |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 202ms | 187 KB | 71% | $3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 191ms | 145 KB | 45% | $3/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 139ms | 46 KB | — | $2/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 126ms | 97 KB | 34% | $2/mo | Optional |
cmp.inmobi.com cmp.inmobi.com | Other | 118ms | 112 KB | 67% | $2/mo | Optional |
c.amazon-adsystem.com c.amazon-adsystem.com | Other | 111ms | 91 KB | 55% | $1/mo | Optional |
www.googletagservices.com www.googletagservices.com | Other | 65ms | 34 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- www.gstatic.com adds 977ms and costs ~$13/month
- Unattributable adds 752ms and costs ~$10/month
- cdn.fuseplatform.net adds 419ms and costs ~$6/month
- geo.cookie-script.com adds 346ms and costs ~$5/month
- cdn.fuseplatform.net adds 254ms and costs ~$3/month
- Google Tag Manager adds 211ms and costs ~$3/month
- securepubads.g.doubleclick.net adds 202ms and costs ~$3/month
86% 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.gstatic.com takes 977ms 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
Unattributable takes 752ms 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
cdn.fuseplatform.net takes 419ms 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
geo.cookie-script.com takes 346ms 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
73% of Stripe'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
cdn.fuseplatform.net takes 254ms 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
77% of cdn.fuseplatform.net'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
Google Tag Manager takes 211ms 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
securepubads.g.doubleclick.net takes 202ms 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
71% of securepubads.g.doubleclick.net'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
67% of cmp.inmobi.com'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
55% of c.amazon-adsystem.com'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