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.
1.46 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.96 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
21 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.580
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.46 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.
2.84 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DPage Weight InventoryAction41 resources · 2.0 MB · 162 KB savings availableFIX
~161.5 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 41 resources | 2.0 MiB | ||||||
CPage Weight BudgetAction2.0 MB transferred, 41 requestsREVIEW
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
CImage OptimizationAction7 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
BJS Execution Cost517ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.rpi.edu/ | 133ms | 2ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-TTXBMVKEJW&cx=c>m=4e64h1 | 95ms | 79ms | 15ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-WDDXF257 | 79ms | 64ms | 13ms | 3rd |
| Unattributable | 79ms | 2ms | 0ms | 3rd |
| https://rensselaer-polytechnic-institute.contact-server.com/mtc.js | 69ms | 47ms | 0ms | 3rd |
| https://scripts.clarity.ms/0.8.59/clarity.js | 62ms | 53ms | 3ms | 3rd |
CJS BundlesAction13 scripts, 162 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-TTXBMVKEJW&cx=c>m=4e64h1 | 169 KB | 68 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-WDDXF257 | 127 KB | 60 KB (47%) | ✓ | 3rd |
| https://www.rpi.edu/sites/default/files/js/js_eSuyrTxcfusFaXjeggWsR2y0YuNdX4BfMpfK7YKizCI.js?scope=footer&delta=1&language=en&theme=rpi&include=eJxLz89Pz0mNL0lM108HEjrpqHy9xKzEClTBXJ2igkz9pPz8kuKSosQCMC89Jz8pMUe3uKQyJzMvHQBaliBg | 42 KB | 34 KB (80%) | ✓ | 3rd |
| https://alert.rpi.edu/alerts.js?_=1776810903071 | 0 KB | — | ✓ | 3rd |
| https://www.rpi.edu/core/assets/vendor/jquery/jquery.min.js?v=4.0.0 | 32 KB | — | ✓ | 3rd |
| https://www.rpi.edu/modules/contrib/google_tag/js/gtm.js?tduvt5 | 1 KB | — | ✓ | 3rd |
| https://www.rpi.edu/sites/default/files/js/js_DNi57yiLLaas9DLermymPAhNQkAm8dw7Wh_LjN8WlrA.js?scope=header&delta=0&language=en&theme=rpi&include=eJxLz89Pz0mNL0lM108HEjrpqHy9xKzEClTBXJ2igkz9pPz8kuKSosQCMC89Jz8pMUe3uKQyJzMvHQBaliBg | 0 KB | — | ✓ | 3rd |
| https://www.clarity.ms/tag/rxfz2i6zpq?ref=gtm | 1 KB | — | ✓ | 3rd |
| https://www.rpi.edu/modules/contrib/google_tag/js/gtag.js?tduvt5 | 1 KB | — | ✓ | 3rd |
| https://adp.eab.com/js/adp.min.js | 0 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
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 Loading7 fonts (1024 KB)PASS
Web fonts
7
1024 KB total
Render-blocking
0
of 7
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
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 ~452 KB and ~904 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
AHTTP Cachingmax-age=86400 (1 day)PASS
public, max-age=86400
| Directive | Value | Meaning |
|---|---|---|
| public | — | Any cache may store this response |
| max-age | 86400 | Cache for 1 day |
Network Waterfall41 requests over 2129msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.rpi.edu www.rpi.edu | Other | 133ms | 10 KB | — | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 95ms | 169 KB | 40% | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 79ms | 127 KB | 47% | €1/mo | Optional |
Unattributable Unattributable | Other | 79ms | 0 KB | — | €1/mo | Optional |
rensselaer-polytechnic-institute.contact-server.com rensselaer-polytechnic-institute.contact-server.com | Other | 69ms | 4 KB | — | €1/mo | Optional |
Microsoft Clarity scripts.clarity.ms | Session Replay | 62ms | 26 KB | — | €1/mo | Optional |
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