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.
16.25 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
28.53 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
6 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.050
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
16.25 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.
33.30 s
Page Load Progression
FPage Weight BudgetAction21.3 MB transferred, 99 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
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
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
DJS Execution CostAction2942ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 711ms | 73ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-K826VG | 602ms | 530ms | 59ms | 3rd |
| https://ucsd.edu/ | 593ms | 54ms | 5ms | 1st |
| https://www.googletagmanager.com/gtag/js?id=AW-17658733768&cx=c>m=4e64h1 | 226ms | 199ms | 26ms | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMA.js | 209ms | 156ms | 50ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-ZBPHLZYTS4&cx=c>m=4e64h1 | 208ms | 174ms | 32ms | 3rd |
| https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js | 135ms | 93ms | 8ms | 3rd |
| https://script.hotjar.com/modules.6a0f3932cb1341a35c18.js | 134ms | 111ms | 19ms | 3rd |
| https://www.ucsd.edu/_resources/js/myscripts.js | 125ms | 81ms | 3ms | 3rd |
DJS BundlesAction25 scripts, 323 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-ZBPHLZYTS4&cx=c>m=4e64h1 | 153 KB | 63 KB (41%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-K826VG | 174 KB | 59 KB (34%) | ✓ | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMA.js | 106 KB | 57 KB (54%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-17658733768&cx=c>m=4e64h1 | 146 KB | 55 KB (38%) | ✓ | 3rd |
| https://script.hotjar.com/modules.6a0f3932cb1341a35c18.js | 57 KB | 38 KB (67%) | ✓ | 3rd |
| https://www.ucsd.edu/_resources/bootstrap/javascripts/bootstrap.min.js | 36 KB | 30 KB (82%) | ✓ | 3rd |
| https://www.ucsd.edu/_resources/js/myscripts.js | 38 KB | 21 KB (55%) | ✗ | 3rd |
| https://snap.licdn.com/li.lms-analytics/insight.min.js | 19 KB | — | ✓ | 3rd |
| https://www.youtube.com/iframe_api | 4 KB | — | ✓ | 3rd |
| https://www.ucsd.edu/_resources/js/vendor/flipcards.js | 6 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
DHTTP CachingActionno-store (uncacheable)FIX
max-age=0, no-cache, no-store, must-revalidate
| Directive | Value | Meaning |
|---|---|---|
| max-age | 0 | Cache for 0 seconds |
| no-cache | — | Cache but always revalidate first |
| no-store | — | Never cache this response |
| must-revalidate | — | Must recheck with server after expiry |
CImage OptimizationAction33 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
CPage Weight InventoryAction99 resources · 21.3 MB · 323 KB savings availableREVIEW
~322.8 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 99 resources | 21.3 MiB | ||||||
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Third-Party Impact18% third-party, 0 ms blockingPASS
A+Text CompressionAll text resources are compressedPASS
A+Font Loading4 fonts (152 KB)PASS
Web fonts
4
152 KB total
Render-blocking
0
of 4
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 ~7 KB and ~14 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
Network Waterfall99 requests over 4379msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 711ms | 0 KB | — | $9/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 602ms | 174 KB | 34% | $8/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 226ms | 146 KB | 38% | $3/mo | Costly |
analytics.tiktok.com analytics.tiktok.com | Other | 209ms | 106 KB | 54% | $3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 208ms | 153 KB | 41% | $3/mo | Costly |
ajax.googleapis.com ajax.googleapis.com | Other | 135ms | 33 KB | — | $2/mo | Optional |
Hotjar script.hotjar.com | Session Replay | 134ms | 57 KB | 67% | $2/mo | Optional |
www.ucsd.edu www.ucsd.edu | Other | 125ms | 38 KB | 55% | $2/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 711ms and costs ~$9/month
- Google Tag Manager adds 602ms and costs ~$8/month
- Google Tag Manager adds 226ms and costs ~$3/month
- analytics.tiktok.com adds 209ms and costs ~$3/month
- Google Tag Manager adds 208ms and costs ~$3/month
80% 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
Unattributable takes 711ms 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
Google Tag Manager takes 602ms 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
Google Tag Manager takes 226ms 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
analytics.tiktok.com takes 209ms 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
54% of analytics.tiktok.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
Google Tag Manager takes 208ms 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
67% of Hotjar'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 www.ucsd.edu'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