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.
900 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.75 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
41 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.
1.24 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.
2.51 s
Page Load Progression
DPage Weight BudgetAction2.4 MB transferred, 111 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 ImpactAction67% third-party, 0 ms blockingFIX
DJS BundlesAction33 scripts, 352 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://cdn.amplitude.com/libs/plugin-session-replay-browser-1.23.2-min.js.gz | 130 KB | 82 KB (63%) | ✓ | 3rd |
| https://www.rice.edu/themes/custom/adm_rice/assets/js/app.js?v=10.6.3 | 87 KB | 69 KB (88%) | ✓ | 1st |
| https://www.googletagmanager.com/gtm.js?id=GTM-PH9QMD3 | 144 KB | 64 KB (44%) | ✓ | 3rd |
| https://www.google.com/cse/static/element/dc329f57de078f5d/cse_element__en.js?usqp=CAM%3D | 103 KB | 52 KB (50%) | ✓ | 3rd |
| https://cdn.jsdelivr.net/npm/plyr@3.7.2/dist/plyr.polyfilled.min.js | 36 KB | 32 KB (91%) | ✓ | 3rd |
| https://cse.google.com/adsense/search/async-ads.js | 44 KB | 32 KB (73%) | ✓ | 3rd |
| https://static.addtoany.com/menu/modules/core.ydpp7jcu.js | 26 KB | 21 KB (82%) | ✓ | 3rd |
| https://www.rice.edu/themes/custom/adm_rice/assets/js/extras.js?v=10.6.3 | 1 KB | — | ✓ | 1st |
| https://cse.google.com/cse.js?cx=014332935913219502104:djq0abwo2eq | 4 KB | — | ✓ | 3rd |
| https://www.rice.edu/modules/contrib/google_tag/js/gtm.js?tcvtx0 | 1 KB | — | ✓ | 1st |
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 InventoryAction111 resources · 2.4 MB · 352 KB savings availableFIX
~352.0 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 111 resources | 2.4 MiB | ||||||
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.
Performance issues directly impact user engagement and conversion rates.
CJS Execution CostAction1027ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://cdn.amplitude.com/libs/plugin-session-replay-browser-1.23.2-min.js.gz | 364ms | 320ms | 17ms | 3rd |
| https://www.rice.edu/ | 230ms | 27ms | 2ms | 1st |
| Unattributable | 219ms | 9ms | 0ms | 3rd |
| https://www.rice.edu/sites/g/files/bxs2566/files/js/js_aBqya4AT2_6yges7zY5xaWUqJLOaC_h1jDrpRECxpXc.js?scope=header&delta=0&language=en&theme=adm_rice&include=eJxdi1EKgCAQBS8k7pHk5dpi6S6IH9npK4qgfoZ5Aw_M3aCD8Iifm2l34Bpajomk2ITi4po4d2sBMVrjbEqv3Zek7MRMSgodQnLivz0WbN9YXcE-6MIBxNk1xA | 121ms | 82ms | 3ms | 1st |
| https://www.googletagmanager.com/gtm.js?id=GTM-PH9QMD3 | 92ms | 77ms | 12ms | 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 Loading11 fonts (350 KB)PASS
Web fonts
11
350 KB total
Render-blocking
0
of 11
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+HTTP Cachingmax-age=31536000 (52 weeks)PASS
max-age=31536000, public
| Directive | Value | Meaning |
|---|---|---|
| max-age | 31536000 | Cache for 52 weeks |
| public | — | Any cache may store this response |
Network Waterfall111 requests over 2221msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Amplitude cdn.amplitude.com | Analytics | 364ms | 130 KB | 63% | €4/mo | Costly |
Unattributable Unattributable | Other | 219ms | 0 KB | — | €2/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 92ms | 144 KB | 44% | €1/mo | Optional |
These scripts may cost more than they're worth
- Amplitude adds 364ms and costs ~€4/month
- Unattributable adds 219ms and costs ~€2/month
66% of JavaScript execution time comes from third-party scripts.
Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.
Learn more ▾ ▴
Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.
Source: web.dev / HTTP Archive Web Almanac
Amplitude takes 364ms 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
63% of Amplitude'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
Unattributable takes 219ms 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