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.
1.27 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.55 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
0 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.001
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.59 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.
1.55 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DPage Weight InventoryAction103 resources · 2.0 MB · 206 KB savings availableFIX
~206.0 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 103 resources | 2.0 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CPage Weight BudgetAction2.0 MB transferred, 103 requestsREVIEW
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
CImage OptimizationAction39 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
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 Cost818ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.retaildive.com/ | 265ms | 76ms | 9ms | 3rd |
| https://cmp.osano.com/AzqdtLT8Mqkut2TZ/991974d1-3bca-4b6d-93e4-fc7f0c35945c/osano.js | 166ms | 142ms | 4ms | 3rd |
| Unattributable | 145ms | 3ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-M826LBDJHP&cx=c>m=4e64k1 | 92ms | 81ms | 10ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-55G8WRR | 78ms | 65ms | 12ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-WCZ4CFR>m=4e64k1 | 72ms | 60ms | 11ms | 3rd |
CJS BundlesAction40 scripts, 206 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtm.js?id=GTM-WCZ4CFR>m=4e64k1 | 177 KB | 67 KB (38%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-M826LBDJHP&cx=c>m=4e64k1 | 169 KB | 65 KB (39%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-55G8WRR | 146 KB | 52 KB (36%) | ✓ | 3rd |
| https://www.retaildive.com/static/js/jquery_360.min.js?313321260226 | 35 KB | 22 KB (62%) | ✓ | 3rd |
| https://www.retaildive.com/static/js/dist/sendEmailToLytics.bundle.js?360116090426 | 1 KB | — | ✓ | 3rd |
| https://www.retaildive.com/static/js/divecounter.js?561916200326 | 5 KB | — | ✓ | 3rd |
| https://www.retaildive.com/static/js/dist/signupReferrer.bundle.js?360116090426 | 1 KB | — | ✓ | 3rd |
| https://www.retaildive.com/static/js/prestitial.js?313321260226 | 2 KB | — | ✓ | 3rd |
| https://www.retaildive.com/static/js/dist/onBoardDiagnostics.bundle.js?360116090426 | 2 KB | — | ✓ | 3rd |
| https://www.retaildive.com/static/js/dist/navSignupHelper.bundle.js?360116090426 | 1 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
A+Text CompressionAll text resources are compressedPASS
A+Font Loading6 fonts (255 KB)PASS
Web fonts
6
255 KB total
Render-blocking
0
of 6
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+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall103 requests over 2398msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.retaildive.com www.retaildive.com | Other | 265ms | 63 KB | — | $4/mo | Costly |
cmp.osano.com cmp.osano.com | Other | 166ms | 54 KB | — | $2/mo | Optional |
Unattributable Unattributable | Other | 145ms | 0 KB | — | $2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 92ms | 169 KB | 39% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 78ms | 146 KB | 36% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 72ms | 177 KB | 38% | $1/mo | Optional |
These scripts may cost more than they're worth
- www.retaildive.com adds 265ms and costs ~$4/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.retaildive.com takes 265ms 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