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.
1.15 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.61 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
20 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.
1.35 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.
2.64 s
Page Load Progression
375 ms
750 ms
1.1 s
1.5 s 1.9 s 2.2 s 2.6 s 3.0 sFPage Weight BudgetAction37.3 MB transferred, 116 requestsFIX
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 ImpactAction98% third-party, 0 ms blockingFIX
FJS BundlesAction17 scripts, 633 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://apps.apple.com/assets/index~JZsYzCL4Hi.js | 611 KB | 448 KB (74%) | ✓ | 1st |
| https://js-cdn.music.apple.com/hls.js/2.820.0/hls.js/hls.js | 252 KB | 135 KB (54%) | ✓ | 3rd |
| https://apps.apple.com/assets/index~BRTBTu87nN.js | 71 KB | 50 KB (71%) | ✓ | 1st |
| https://apps.apple.com/assets/mt-metricskit-processor-clickstream.esm~BRd_H7lt9Y.js | 13 KB | — | ✓ | 1st |
| https://apps.apple.com/assets/mt-client-logger-core.esm~-rJfHcY8Zf.js | 1 KB | — | ✓ | 1st |
| https://apps.apple.com/assets/mt-client-logger-core.esm~C76Ol5FZ_o.js | 7 KB | — | ✓ | 1st |
| https://apps.apple.com/assets/mt-metricskit-delegates-html.esm~B1tIUL6Qon.js | 1 KB | — | ✓ | 1st |
| https://apps.apple.com/assets/mt-client-config~B_wygIrM5o.js | 3 KB | — | ✓ | 1st |
| https://apps.apple.com/assets/mt-perfkit.esm~BKZoTKymeC.js | 5 KB | — | ✓ | 1st |
| https://apps.apple.com/assets/mt-metricskit-utils-private.esm~DkzakSThTT.js | 5 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
FPage Weight InventoryAction116 resources · 37.3 MB · 633 KB savings availableFIX
~633.3 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 116 resources | 37.3 MiB | ||||||
CJS Execution CostAction1862ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 602ms | 63ms | 0ms | 3rd |
| https://apps.apple.com/assets/index~BRTBTu87nN.js | 432ms | 269ms | 0ms | 1st |
| https://js-cdn.music.apple.com/hls.js/2.820.0/hls.js/hls.js | 325ms | 262ms | 16ms | 3rd |
| https://apps.apple.com/assets/index~JZsYzCL4Hi.js | 257ms | 156ms | 2ms | 1st |
| https://apps.apple.com/us/iphone/today | 246ms | 4ms | 0ms | 1st |
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Image Optimization41 images, 0 KB saveablePASS
A+Font Loading4 fonts (424 KB)PASS
Web fonts
4
424 KB total
Render-blocking
0
of 4
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
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 ~203 KB and ~406 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
AHTTP Cachingmax-age=60 (1 minute)PASS
max-age=60
| Directive | Value | Meaning |
|---|---|---|
| max-age | 60 | Cache for 1 minute |
Network Waterfall116 requests over 8466msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 602ms | 0 KB | — | $3/mo | Costly |
js-cdn.music.apple.com js-cdn.music.apple.com | Other | 325ms | 252 KB | 54% | $2/mo | Costly |
These scripts may cost more than they're worth
- Unattributable adds 602ms and costs ~$3/month
- js-cdn.music.apple.com adds 325ms and costs ~$2/month
50% 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
Unattributable takes 602ms 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
js-cdn.music.apple.com takes 325ms 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
54% of js-cdn.music.apple.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