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.
11.86 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
23.90 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
886 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.019
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
11.86 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.
25.84 s
Page Load Progression
FPage Weight BudgetAction7.3 MB transferred, 144 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
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
FJS Execution CostAction4332ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 765ms | 655ms | 75ms | 3rd |
| Unattributable | 583ms | 36ms | 0ms | 3rd |
| https://www.wbur.org/ | 536ms | 10ms | 0ms | 3rd |
| https://static.wbur.org/app/prod/_next/static/chunks/framework-3671d8951bf44e4e.js | 488ms | 397ms | 11ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-PCRWWRR>m_auth=uz7j-0KOdZdWUQEvD6ZYtA>m_preview=env-2>m_cookies_win=x | 338ms | 269ms | 57ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-4MF3ZX6E9G&cx=c>m=4e64h1 | 247ms | 206ms | 39ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-XGZ99F1SED&cx=c>m=4e64h1 | 229ms | 199ms | 29ms | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604200101/pubads_impl.js?cb=31097964 | 193ms | 130ms | 51ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-18020114546&cx=c>m=4e64h1 | 185ms | 155ms | 29ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-W6G65JFZ | 180ms | 146ms | 32ms | 3rd |
Showing top 10 of 17 scripts
FJS BundlesAction72 scripts, 1.0 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 0 KB | 177 KB (49%) | ✓ | 3rd |
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 362 KB | 177 KB (49%) | ✓ | 3rd |
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 362 KB | 177 KB (49%) | ✓ | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604200101/pubads_impl.js?cb=31097964 | 188 KB | 143 KB (76%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-4MF3ZX6E9G&cx=c>m=4e64h1 | 165 KB | 67 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-PCRWWRR>m_auth=uz7j-0KOdZdWUQEvD6ZYtA>m_preview=env-2>m_cookies_win=x | 164 KB | 64 KB (39%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-XGZ99F1SED&cx=c>m=4e64h1 | 147 KB | 64 KB (43%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-W6G65JFZ | 134 KB | 63 KB (47%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-18020114546&cx=c>m=4e64h1 | 137 KB | 62 KB (45%) | ✓ | 3rd |
| https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js | 54 KB | 36 KB (67%) | ✓ | 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
FPage Weight InventoryAction144 resources · 7.3 MB · 1.0 MB savings availableFIX
~1.0 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 144 resources | 7.3 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization36 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
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 Loading5 fonts (135 KB)PASS
Web fonts
5
135 KB total
Render-blocking
0
of 5
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 Hints15 hints, 0 missing preconnectsPASS
Current Resource Hints
15 resource hints configured
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall144 requests over 2035msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.gstatic.com www.gstatic.com | Other | 765ms | 0 KB | 49% | €8/mo | Costly |
Unattributable Unattributable | Other | 583ms | 0 KB | — | €6/mo | Costly |
www.wbur.org www.wbur.org | Other | 536ms | 209 KB | — | €6/mo | Costly |
static.wbur.org static.wbur.org | Other | 488ms | 45 KB | — | €5/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 338ms | 164 KB | 39% | €4/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 247ms | 165 KB | 40% | €3/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 229ms | 147 KB | 43% | €2/mo | Costly |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 193ms | 188 KB | 76% | €2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 185ms | 137 KB | 45% | €2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 180ms | 134 KB | 47% | €2/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 125ms | 44 KB | — | €1/mo | Optional |
static.chartbeat.com static.chartbeat.com | Other | 112ms | 16 KB | — | €1/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 101ms | 97 KB | 35% | €1/mo | Optional |
cb9825.wbur.org cb9825.wbur.org | Other | 77ms | 2 KB | — | €1/mo | Optional |
static.wbur.org static.wbur.org | Other | 61ms | 27 KB | — | €1/mo | Optional |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 61ms | 34 KB | — | €1/mo | Optional |
pagead2.googlesyndication.com pagead2.googlesyndication.com | Other | 50ms | 54 KB | 67% | €1/mo | Optional |
These scripts may cost more than they're worth
- www.gstatic.com adds 765ms and costs ~€8/month
- Unattributable adds 583ms and costs ~€6/month
- www.wbur.org adds 536ms and costs ~€6/month
- static.wbur.org adds 488ms and costs ~€5/month
- Google Tag Manager adds 338ms and costs ~€4/month
- Google Tag Manager adds 247ms and costs ~€3/month
- Google Tag Manager adds 229ms and costs ~€2/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.gstatic.com takes 765ms 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 583ms 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
www.wbur.org takes 536ms 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
static.wbur.org takes 488ms 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 338ms 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 247ms 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 229ms 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
76% of securepubads.g.doubleclick.net'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
67% of pagead2.googlesyndication.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