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.
5.26 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
12.56 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
655 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.015
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
5.85 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.
16.57 s
Page Load Progression
FPage Weight BudgetAction3.6 MB transferred, 62 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
DThird-Party ImpactAction98% third-party, 0 ms blockingFIX
DJS Execution CostAction3405ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://royalsocietypublishing.org/ | 762ms | 38ms | 7ms | 1st |
| https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js | 469ms | 351ms | 101ms | 3rd |
| Unattributable | 371ms | 68ms | 0ms | 3rd |
| https://trs.silverchair-cdn.com/Themes/Client/app/jsdist/v-639116431184716663/site.min.js | 310ms | 75ms | 47ms | 3rd |
| https://cookie-cdn.cookiepro.com/scripttemplates/202511.1.0/otBannerSdk.js | 280ms | 192ms | 47ms | 3rd |
| https://js.stripe.com/v3/ | 258ms | 160ms | 95ms | 3rd |
| https://royalsocietypublishing.org/cdn-cgi/challenge-platform/scripts/jsd/main.js | 247ms | 237ms | 3ms | 1st |
| https://www.googletagmanager.com/gtag/js?id=G-VYDHG8C6QY&cx=c>m=4e64h1 | 243ms | 204ms | 36ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TFQX55T7 | 187ms | 144ms | 40ms | 3rd |
| https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js | 187ms | 135ms | 8ms | 3rd |
Showing top 10 of 11 scripts
FJS BundlesAction15 scripts, 581 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://js.stripe.com/v3/ | 220 KB | 160 KB (73%) | ✓ | 3rd |
| https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js | 251 KB | 122 KB (49%) | ✓ | 3rd |
| https://trs.silverchair-cdn.com/Themes/Client/app/jsdist/v-639116431184716663/site.min.js | 135 KB | 104 KB (77%) | ✓ | 3rd |
| https://cookie-cdn.cookiepro.com/scripttemplates/202511.1.0/otBannerSdk.js | 125 KB | 66 KB (53%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-VYDHG8C6QY&cx=c>m=4e64h1 | 157 KB | 66 KB (42%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TFQX55T7 | 133 KB | 63 KB (47%) | ✓ | 3rd |
| https://widgets.figshare.com/static/figshare.js | 36 KB | — | ✓ | 3rd |
| https://cookie-cdn.cookiepro.com/consent/01980ead-9999-7ec5-8307-69ac7b4ebd59/01980ead-9999-7ec5-8307-69ac7b4ebd59.json | 3 KB | — | ✓ | 3rd |
| https://trs.silverchair-cdn.com/Themes/Silver/app/vendor/v-639102489972463725/jquery-migrate-3.1.0.min.js | 4 KB | — | ✓ | 3rd |
| https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js | 31 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
FPage Weight InventoryAction62 resources · 3.6 MB · 581 KB savings availableFIX
~580.8 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 62 resources | 3.6 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction19 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
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 Loading6 fonts (177 KB)PASS
Web fonts
6
177 KB total
Render-blocking
0
of 6
Dominant font-display
swap
Most common across fonts
Font loading timeline
- 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 ~6 KB and ~12 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 Waterfall62 requests over 2623msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
jsDelivr cdn.jsdelivr.net | CDN | 469ms | 251 KB | 49% | $6/mo | Costly |
Unattributable Unattributable | Other | 371ms | 0 KB | — | $5/mo | Costly |
trs.silverchair-cdn.com trs.silverchair-cdn.com | Other | 310ms | 135 KB | 77% | $4/mo | Costly |
cookie-cdn.cookiepro.com cookie-cdn.cookiepro.com | Other | 280ms | 125 KB | 53% | $4/mo | Costly |
Stripe js.stripe.com | Payment | 258ms | 220 KB | 73% | $3/mo | Essential |
Google Tag Manager www.googletagmanager.com | Tag Manager | 243ms | 157 KB | 42% | $3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 187ms | 133 KB | 47% | $2/mo | Optional |
ajax.googleapis.com ajax.googleapis.com | Other | 187ms | 31 KB | — | $2/mo | Optional |
widgets.figshare.com widgets.figshare.com | Other | 91ms | 36 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- jsDelivr adds 469ms and costs ~$6/month
- Unattributable adds 371ms and costs ~$5/month
- trs.silverchair-cdn.com adds 310ms and costs ~$4/month
- cookie-cdn.cookiepro.com adds 280ms and costs ~$4/month
- Google Tag Manager adds 243ms and costs ~$3/month
70% 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
jsDelivr takes 469ms 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 371ms 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
trs.silverchair-cdn.com takes 310ms 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 trs.silverchair-cdn.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
cookie-cdn.cookiepro.com takes 280ms 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
53% of cookie-cdn.cookiepro.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
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
Google Tag Manager takes 243ms 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