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.
2.36 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
4.43 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
22 ms
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.
3.17 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.
5.07 s
Page Load Progression
FPage Weight BudgetAction5.9 MB transferred, 104 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
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 BundlesAction34 scripts, 343 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-1XQYSMEBVE&cx=c>m=4e64h1 | 175 KB | 67 KB (39%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=AW-10975680821&cx=c>m=4e64h1 | 145 KB | 60 KB (42%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-5Q36JQ | 180 KB | 56 KB (31%) | ✓ | 3rd |
| https://www.google.com/cse/static/element/dc329f57de078f5d/cse_element__en.js?usqp=CAM%3D | 103 KB | 53 KB (52%) | ✓ | 3rd |
| https://cse.google.com/adsense/search/async-ads.js | 44 KB | 32 KB (73%) | ✓ | 3rd |
| https://resources.usersnap.com/widget-assets/js/entries/globalSetup/8fa14b1d6833454c.js | 72 KB | 29 KB (40%) | ✓ | 3rd |
| https://www.cmu.edu/core/assets/vendor/jquery/jquery.min.js?v=4.0.0 | 35 KB | 25 KB (73%) | ✓ | 3rd |
| https://www.cmu.edu/themes/custom/cmu_base/dist/assets/script2.js | 32 KB | 21 KB (67%) | ✗ | 3rd |
| https://www.cmu.edu/sites/default/files/js/js_f7uEGQuEyNe0IGXBmhsrFjCpvefxAjYDlKohWT3lisY.js?scope=footer&delta=4&language=en&theme=cmu_base&include=eJxtjksOwzAIRC_kxkdCJKEOETaVIW5y-7pZtOpnM4LRYwY0IwcuK02uNa42XHkHalQctioW8AfQRrXyTDCjd2G7CR6dgIxlQwHhRvcFhcD6DWv5k2HsxHOY8gYjGsUkOqJczA_hkk6_p2MPphrPb-w0nwDF1xTe0EgLNtZqIammXu6YYuryvQ-44v5p5gepYWdm | 5 KB | — | ✓ | 3rd |
| https://widget.usersnap.com/global/load/c459e901-629d-40c0-8e0f-ac7766bdb46d?onload=onUsersnapLoad | 4 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
DPage Weight InventoryAction104 resources · 5.9 MB · 343 KB savings availableFIX
~342.6 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 104 resources | 5.9 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization35 images, 0 KB saveableREVIEW
CJS Execution CostAction1274ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.cmu.edu/ | 432ms | 3ms | 1ms | 3rd |
| Unattributable | 230ms | 7ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-5Q36JQ | 161ms | 129ms | 15ms | 3rd |
| https://www.cmu.edu/themes/custom/cmu_base/dist/assets/script.js?v=11.3.5 | 109ms | 21ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=AW-10975680821&cx=c>m=4e64h1 | 103ms | 94ms | 9ms | 3rd |
| https://scripts.clarity.ms/0.8.59/clarity.js | 81ms | 70ms | 3ms | 3rd |
| https://cse.google.com/cse.js?cx=ff2cbc6f33e7e5678 | 55ms | 27ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-1XQYSMEBVE&cx=c>m=4e64h1 | 51ms | 39ms | 12ms | 3rd |
| https://events.cmu.edu/live/resource/js/%5Clivewhale%5Cthirdparty%5Cjquery%5Cjquery.no-conflict-header.js/%5Clivewhale%5Cthirdparty%5Cjquery%5Cjquery.js/%5Clivewhale%5Cthirdparty%5Cjquery%5Cjquery.no-conflict-footer.js/%5Clivewhale%5Cscripts%5Clib%5Cdate%5Cformatter.js/%5Clivewhale%5Cscripts%5Clib%5Cdate%5Ctimezone.js/%5Clivewhale%5Cscripts%5Clib%5Cdate%5Cuser.js/%5Clivewhale%5Cplugins%5Cjquery%5Cjquery.lw-widget.js | 51ms | 22ms | 4ms | 3rd |
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading6 fonts (218 KB)PASS
Web fonts
6
218 KB total
Render-blocking
0
of 6
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
Network Waterfall104 requests over 5161msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.cmu.edu www.cmu.edu | Other | 432ms | 29 KB | — | $6/mo | Costly |
Unattributable Unattributable | Other | 230ms | 0 KB | — | $3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 161ms | 180 KB | 31% | $2/mo | Optional |
www.cmu.edu www.cmu.edu | Other | 109ms | 13 KB | — | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 103ms | 145 KB | 42% | $1/mo | Optional |
Microsoft Clarity scripts.clarity.ms | Session Replay | 81ms | 26 KB | — | $1/mo | Optional |
cse.google.com cse.google.com | Other | 55ms | 4 KB | — | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 51ms | 175 KB | 39% | $1/mo | Optional |
events.cmu.edu events.cmu.edu | Other | 51ms | 36 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- www.cmu.edu adds 432ms and costs ~$6/month
- Unattributable adds 230ms 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.cmu.edu takes 432ms 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 230ms 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