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.
2.41 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
5.04 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.70 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.029
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.44 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.
5.16 s
Page Load Progression
FPage Weight BudgetAction3.9 MB transferred, 181 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
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS Execution CostAction2600ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.oclc.org/etc.clientlibs/oclc/clientlibs/oclc/jquery.min.js | 1829ms | 1826ms | 2ms | 3rd |
| https://www.oclc.org/en/home.html?redirect=true | 408ms | 209ms | 26ms | 3rd |
| Unattributable | 245ms | 52ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TC83QFB | 117ms | 99ms | 15ms | 3rd |
FJS BundlesAction119 scripts, 979 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.oclc.org/etc.clientlibs/clientlibs/social/thirdparty/ckeditor.min.js | 232 KB | 202 KB (87%) | ✓ | 3rd |
| https://static.cloud.coveo.com/headless/v3.49.3/headless.esm.js | 170 KB | 123 KB (73%) | ✓ | 3rd |
| https://www.oclc.org/apps/oclc/clientlibs/oclc/jquery-ui/source/jquery-ui.min.js | 0 KB | 113 KB (86%) | ✗ | 3rd |
| https://www.oclc.org/apps/oclc/clientlibs/oclc/jquery-ui/source/jquery-ui.min.js | 695 KB | 113 KB (86%) | ✗ | 3rd |
| https://www.oclc.org/apps/oclc/clientlibs/oclc/jquery-ui/source/jquery-ui.min.js | 132 KB | 113 KB (86%) | ✗ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TC83QFB | 188 KB | 85 KB (45%) | ✓ | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202505.1.0/otBannerSdk.js | 119 KB | 75 KB (63%) | ✓ | 3rd |
| https://www.oclc.org/etc.clientlibs/clientlibs/granite/jquery-ui.min.js | 70 KB | 60 KB (87%) | ✓ | 3rd |
| https://www.oclc.org/apps/oclc/clientlibs/oclc/jquery-ui.min.js | 68 KB | 59 KB (87%) | ✓ | 3rd |
| https://static.cloud.coveo.com/atomic/v3/npm.dayjs-2661949a.js | 42 KB | 36 KB (99%) | ✓ | 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 InventoryAction181 resources · 3.9 MB · 979 KB savings availableFIX
~978.9 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 181 resources | 3.9 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction25 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
A+Text CompressionAll text resources are compressedPASS
A+Font Loading5 fonts (164 KB)PASS
Web fonts
5
164 KB total
Render-blocking
0
of 5
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+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall181 requests over 10054msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.oclc.org www.oclc.org | Other | 1829ms | 32 KB | — | €29/mo | Costly |
www.oclc.org www.oclc.org | Other | 408ms | 15 KB | — | €7/mo | Costly |
Unattributable Unattributable | Other | 245ms | 0 KB | — | €4/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 117ms | 188 KB | 45% | €2/mo | Optional |
These scripts may cost more than they're worth
- www.oclc.org adds 1829ms and costs ~€29/month
- www.oclc.org adds 408ms and costs ~€7/month
- Unattributable adds 245ms 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.oclc.org takes 1829ms 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.oclc.org takes 408ms 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 245ms 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