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.
844 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.11 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
36 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.059
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.13 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.
1.82 s
Page Load Progression
DPage Weight BudgetAction2.1 MB transferred, 72 requestsFIX
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
DPage Weight InventoryAction72 resources · 2.1 MB · 275 KB savings availableFIX
~274.8 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 72 resources | 2.1 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction27 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
BJS Execution Cost947ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.novartis.com/ | 284ms | 2ms | 1ms | 3rd |
| https://www.novartis.com/sites/novartiscom/files/js/js_RBDtWSKtcMyC24sM1Ge-XKAdIxxptpPPSBX0HfqcIdg.js?scope=footer&delta=0&language=en&theme=cosmos&include=eJx1kmuOpDAMhC8UiDRa7WpPYxlwhzRJjGzDdN9-zPRjXpo_wfU5FYVyUEbLI4wsFPGj7is2TDTBKReCbS2MkzfqWsgIaKdmh_RdU7jb1HhcwKuFJH4WAVXJILczjcYSz9q7Bf68_Pv7H3RmMTCSCtRmbCPV42w-gc0EMwnDjpLRWVbdCLhB5TCQuQfosrLebulSI27GoNtQs_22JVEjwRIGZlMTXGFAkcwxFR6wdGrXklsKI_OSaRWOz8qZVtb4tD7AD-s7bbt2uXqKXcJSSK6PhhbP5SH2PBF3a8FrV7JamNDQhWc40Ix7ZtFAF_ODlzjJtmLp7zIk5uTTMUwx-fJd93jGy1dYQxuhYEubXwuUym0iTzLy1kyuz05Q8lHNgGuGI9vHC4i_8PD-N0B18MQXLLYJxvv3RsMrQaWEPuUtnlhq_0rdAbqDdCfhZtSmN6ZXBd0&0=tdwrnx | 189ms | 122ms | 27ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-57RJQ5 | 143ms | 122ms | 19ms | 3rd |
| Unattributable | 141ms | 32ms | 0ms | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202604.1.0/otBannerSdk.js | 106ms | 76ms | 16ms | 3rd |
| https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js | 84ms | 72ms | 5ms | 3rd |
CJS BundlesAction17 scripts, 275 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.novartis.com/sites/novartiscom/files/js/js_RBDtWSKtcMyC24sM1Ge-XKAdIxxptpPPSBX0HfqcIdg.js?scope=footer&delta=0&language=en&theme=cosmos&include=eJx1kmuOpDAMhC8UiDRa7WpPYxlwhzRJjGzDdN9-zPRjXpo_wfU5FYVyUEbLI4wsFPGj7is2TDTBKReCbS2MkzfqWsgIaKdmh_RdU7jb1HhcwKuFJH4WAVXJILczjcYSz9q7Bf68_Pv7H3RmMTCSCtRmbCPV42w-gc0EMwnDjpLRWVbdCLhB5TCQuQfosrLebulSI27GoNtQs_22JVEjwRIGZlMTXGFAkcwxFR6wdGrXklsKI_OSaRWOz8qZVtb4tD7AD-s7bbt2uXqKXcJSSK6PhhbP5SH2PBF3a8FrV7JamNDQhWc40Ix7ZtFAF_ODlzjJtmLp7zIk5uTTMUwx-fJd93jGy1dYQxuhYEubXwuUym0iTzLy1kyuz05Q8lHNgGuGI9vHC4i_8PD-N0B18MQXLLYJxvv3RsMrQaWEPuUtnlhq_0rdAbqDdCfhZtSmN6ZXBd0&0=tdwrnx | 184 KB | 122 KB (66%) | ✓ | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202604.1.0/otBannerSdk.js | 131 KB | 69 KB (53%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-57RJQ5 | 183 KB | 56 KB (31%) | ✓ | 3rd |
| https://script.crazyegg.com/pages/versioned/common-scripts/4ce8c7df8d425cc50464576824ed91eb.js | 55 KB | 27 KB (49%) | ✓ | 3rd |
| https://script.crazyegg.com/pages/scripts/0058/0106.js | 3 KB | — | ✓ | 3rd |
| https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 | 11 KB | — | ✓ | 3rd |
| https://cdn.cookielaw.org/consent/fe8dfb2c-2701-45db-8577-13675c68ed60/OtAutoBlock.js | 13 KB | — | ✓ | 3rd |
| https://www.novartis.com/modules/contrib/google_tag/js/gtag.js?tdwrnx | 1 KB | — | ✓ | 3rd |
| https://cdn.cookielaw.org/scripttemplates/otSDKStub.js | 9 KB | — | ✓ | 3rd |
| https://www.youtube.com/s/player/22f02d3d/www-widgetapi.vflset/www-widgetapi.js | 11 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
A+Text CompressionAll text resources are compressedPASS
A+Font Loading3 fonts (104 KB)PASS
Web fonts
3
104 KB total
Render-blocking
0
of 3
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
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 ~31 KB and ~62 ms
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 Waterfall72 requests over 1104msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.novartis.com www.novartis.com | Other | 284ms | 29 KB | — | €3/mo | Costly |
www.novartis.com www.novartis.com | Other | 189ms | 184 KB | 66% | €2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 143ms | 183 KB | 31% | €2/mo | Optional |
Unattributable Unattributable | Other | 141ms | 0 KB | — | €2/mo | Optional |
OneTrust cdn.cookielaw.org | Consent | 106ms | 131 KB | 53% | €1/mo | Essential |
script.crazyegg.com script.crazyegg.com | Other | 84ms | 55 KB | 49% | €1/mo | Optional |
These scripts may cost more than they're worth
- www.novartis.com adds 284ms and costs ~€3/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.novartis.com takes 284ms 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
66% of www.novartis.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
53% of OneTrust'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