Performance
· 21 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.
1.02 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
3.28 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
130 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.510
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.87 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.
5.71 s
Page Load Progression
859 ms
1.7 s
2.6 s
3.4 s
4.3 s 5.2 s
6.0 s
6.9 sFPage Weight BudgetAction7.4 MB transferred, 324 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
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
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 Execution CostAction2837ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 759ms | 169ms | 0ms | 1st |
| https://www.nba.com/_next/static/chunks/framework-ad7abf312d5d61d4.js | 474ms | 319ms | 2ms | 3rd |
| https://www.nba.com/ | 461ms | 16ms | 1ms | 3rd |
| https://www.nba.com/sIQAsPA_H/8qdbfI/HF7R6DI/322Q8/NSL54JarXi/XkZqMkk7BQ/ezoSFD/Z9Ah8V?v=86a2f683-2eb6-6d7a-67c3-84caa4010211 | 346ms | 323ms | 9ms | 3rd |
| https://www.nba.com/_next/static/chunks/pages/_app-133fbdc317e9bad7.js | 333ms | 210ms | 25ms | 3rd |
| https://www.nba.com/sIQAsPA_H/8qdbfI/HF7R6DI/322Q8/YLL54JarXiiwEif7/IllgMkk7BQ/YiBQRX/1Qe08B | 223ms | 201ms | 11ms | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202608110101/pubads_impl.js | 67ms | 40ms | 10ms | 3rd |
| https://stories.usestoryteller.com/amp/20260518.1/amp-story-player-v0.js | 61ms | 49ms | 1ms | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202511.1.0/otBannerSdk.js | 59ms | 22ms | 9ms | 3rd |
| https://tags.nba.com/nba-web/prod/utag.js | 53ms | 48ms | 3ms | 3rd |
FJS BundlesAction72 scripts, 719 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.nba.com/_next/static/chunks/pages/_app-133fbdc317e9bad7.js | 391 KB | 240 KB (61%) | ✓ | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202608110101/pubads_impl.js | 201 KB | 142 KB (70%) | ✓ | 3rd |
| https://siteintercept.qualtrics.com/dxjsmodule/11.f63ef3118b6fa709f80b.chunk.js?Q_CLIENTVERSION=2.41.0&Q_CLIENTTYPE=web&Q_BRANDID=www.nba.com | 89 KB | 79 KB (89%) | ✓ | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202511.1.0/otBannerSdk.js | 124 KB | 71 KB (57%) | ✓ | 3rd |
| https://assets.adobedtm.com/82bf3c13a525/38d894c71c0b/launch-ff3828f362fb.min.js | 125 KB | 54 KB (43%) | ✓ | 3rd |
| https://www.nba.com/sIQAsPA_H/8qdbfI/HF7R6DI/322Q8/NSL54JarXi/XkZqMkk7BQ/ezoSFD/Z9Ah8V?v=86a2f683-2eb6-6d7a-67c3-84caa4010211 | 169 KB | 36 KB (21%) | ✓ | 3rd |
| https://www.nba.com/sIQAsPA_H/8qdbfI/HF7R6DI/322Q8/YLL54JarXiiwEif7/IllgMkk7BQ/YiBQRX/1Qe08B | 173 KB | 34 KB (20%) | ✓ | 3rd |
| https://www.nba.com/_next/static/chunks/85246-8f4d03fb8b8434f9.js | 40 KB | 32 KB (81%) | ✓ | 3rd |
| https://www.nba.com/_next/static/chunks/32044-3c546c2099db1958.js | 66 KB | 31 KB (47%) | ✓ | 3rd |
| https://www.nba.com/_next/static/usjqyudgYZuhI2uTFzj2K/_buildManifest.js | 18 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
FPage Weight InventoryAction324 resources · 7.4 MB · 719 KB savings availableFIX
~718.6 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 324 resources | 7.4 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization205 images, 0 KB saveableREVIEW
CCompression AlgorithmActionMain response served uncompressedREVIEW
BMain HTML Cache-ControlNo Cache-Control header on main HTML responseREVIEW
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
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 Loading2 fonts (61 KB)PASS
Web fonts
2
61 KB total
Render-blocking
0
of 2
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/3 (QUIC)HTTP/3 advertised via Alt-SvcPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Server Response Intelligence1 server-response signal(s) detectedPASS
Network Waterfall324 requests over 4572msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.nba.com www.nba.com | Other | 474ms | 45 KB | — | $6/mo | Costly |
www.nba.com www.nba.com | Other | 461ms | 74 KB | — | $6/mo | Costly |
www.nba.com www.nba.com | Other | 346ms | 169 KB | 21% | $5/mo | Costly |
www.nba.com www.nba.com | Other | 333ms | 391 KB | 61% | $4/mo | Costly |
www.nba.com www.nba.com | Other | 223ms | 2 KB | 20% | $3/mo | Costly |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 67ms | 201 KB | 70% | $1/mo | Optional |
stories.usestoryteller.com stories.usestoryteller.com | Other | 61ms | 23 KB | — | $1/mo | Optional |
OneTrust cdn.cookielaw.org | Consent | 59ms | 124 KB | 57% | $1/mo | Essential |
tags.nba.com tags.nba.com | Other | 53ms | 39 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- www.nba.com adds 474ms and costs ~$6/month
- www.nba.com adds 461ms and costs ~$6/month
- www.nba.com adds 346ms and costs ~$5/month
- www.nba.com adds 333ms and costs ~$4/month
- www.nba.com adds 223ms and costs ~$3/month
73% 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.nba.com takes 474ms 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.nba.com takes 461ms 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.nba.com takes 346ms 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.nba.com takes 333ms 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
61% of www.nba.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
www.nba.com takes 223ms 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
70% 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
57% of OneTrust'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