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https://www.bigcommerce.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
78
GRADE
C
FIX
3
REVIEW
3
PASS
6
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
58
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
86
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
61
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

399 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.51 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

1.65 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.009

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

3.00 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.

5.08 s

Page Load Progression

900 ms
1.8 s
2.7 s
3.6 s
4.5 s
5.4 s
6.3 s
7.2 s
Checks
14
6 PASS 3 REVIEW 3 FIX
F
Page Weight Budget
Action
3.4 MB transferred, 154 requests
FIX
3.4 MB transferred, 154 requests
Warning::
Page weighs 11.0 MB (3.4 MB transferred)
Warning::
JavaScript is 762 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 762 KB
Info::
Fonts are 608 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 608 KB
Warning::
154 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.72 g CO2 per page load
3.4 MB / 2.4 MB budget
3.4 MB transferred
154 requests
0.72 g CO2 per page load
Other 925.2 KiB 26%
Other 855.0 KiB 24%
JavaScript 761.6 KiB 22%
Fonts 607.6 KiB 17%
Images 174.6 KiB 5%
Other 98.0 KiB 3%
HTML 85.3 KiB 2%
CSS 23.0 KiB 1%
0 2.4 MB 4.9 MB
Over budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

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.

Why this matters

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.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

F
JS Execution Cost
Action
5379ms total JS execution
FIX
5379ms total JS execution
Warning::
https://www.bigcommerce.com/_next/static/chunks/fr...: 2957ms CPU time
Warning::
https://www.bigcommerce.com/_next/static/chunks/pa...: 1184ms CPU time
Warning::
Unattributable: 491ms CPU time
Warning::
https://www.bigcommerce.com/: 394ms CPU time
Info::
https://www.bigcommerce.com/_next/static/chunks/75...: 182ms CPU time
Info::
Third-party scripts: 491ms (9% of total)

Main Thread Breakdown

Script Evaluation 71% Other 12% Style & Layout 6% Garbage Collection 4% Rendering 3%
ScriptTotalScriptingParse/CompileParty
https://www.bigcommerce.com/_next/static/chunks/framework-b7b8137fa3a9d31a.js2957ms2741ms5ms1st
https://www.bigcommerce.com/_next/static/chunks/pages/_app-8baf31dee9a7b458.js1184ms705ms60ms1st
Unattributable491ms21ms0ms3rd
https://www.bigcommerce.com/394ms8ms1ms1st
https://www.bigcommerce.com/_next/static/chunks/7554.06f98d95ca62a820.js182ms178ms4ms1st
https://www.bigcommerce.com/_next/static/chunks/main-742be3fa220ac20b.js170ms148ms5ms1st
F
JS Bundles
Action
66 scripts, 560 KB unused
FIX
66 scripts, 560 KB unused
Warning::
https://www.bigcommerce.com/_next/static/chunks/pa...: 196 KB unused (48%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.bigcommerce.com/_next/static/chunks/21...: 118 KB unused (89%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.bigcommerce.com/_next/static/chunks/21...: 118 KB unused (89%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.bigcommerce.com/_next/static/chunks/01...: 45 KB unused (93%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.bigcommerce.com/_next/static/chunks/01...: 45 KB unused (93%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 560 KB
560 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.bigcommerce.com/_next/static/chunks/pages/_app-8baf31dee9a7b458.js414 KB196 KB (48%)✓1st
https://www.bigcommerce.com/_next/static/chunks/2116-50e1b1f0cf02c8d4.js32 KB118 KB (89%)✓1st
https://www.bigcommerce.com/_next/static/chunks/2116-50e1b1f0cf02c8d4.js0 KB118 KB (89%)✓1st
https://www.bigcommerce.com/_next/static/chunks/01587d02-e76a22e6c152deb6.js9 KB45 KB (93%)✓1st
https://www.bigcommerce.com/_next/static/chunks/01587d02-e76a22e6c152deb6.js0 KB45 KB (93%)✓1st
https://www.bigcommerce.com/_next/static/chunks/7554.06f98d95ca62a820.js45 KB38 KB (84%)✓1st
https://www.bigcommerce.com/_next/static/chunks/4380.ad7af82714332598.js1 KB—✓1st
https://www.bigcommerce.com/_next/static/chunks/pages/resources/reports/%5Bslug%5D-1eba9397efa2470e.js4 KB—✓1st
https://www.bigcommerce.com/_next/static/chunks/4759-af481d2f627a72a9.js15 KB—✓1st
https://www.bigcommerce.com/_next/static/chunks/pages/%5B%5B...path%5D%5D-0f732b0ebedefc32.js3 KB—✓1st

Consider code splitting or tree shaking to reduce unused code.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

B
Image Optimization
24 images, 0 KB saveable
REVIEW
24 images, 0 KB saveable
Info::
All images are well-optimized
24 images 175 KB
0 oversized -0 KB
16 legacy format
0 missing dimensions CLS risk
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

B
HTTP Caching
public, max-age=0, must-revalidate
REVIEW
public, max-age=0, must-revalidate
Info::
Cache-Control header is set
Got: public, max-age=0, must-revalidate
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

public, max-age=0, must-revalidate

DirectiveValueMeaning
public—Any cache may store this response
max-age0Cache for 0 seconds
must-revalidate—Must recheck with server after expiry
A
Third-Party Impact
28% third-party, 0 ms blocking
PASS
28% third-party, 0 ms blocking
Info::
Third-party code accounts for 28% of page weight (976.8 KiB of 3.4 MiB)
Info::
Third-party blocking time is low (0 ms)
72%
28%
First-party Third-party
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
15 fonts (608 KB)
PASS
15 fonts (608 KB)
Info::
15 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

15

608 KB total

Render-blocking

0

of 15

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s FCP 399 ms LCP 1.5 shttps://www.bigcommerce.com/mm/fonts/Gotham-Black_Web.woff2Gotham-Black_Web.woff2 https://www.bigcommerce.com/mm/fonts/Gotham-Black_Web.woff2 — 41.3 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/Gotham-Bold_Web.woff2Gotham-Bold_Web.woff2 https://www.bigcommerce.com/mm/fonts/Gotham-Bold_Web.woff2 — 38.6 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/Gotham-Book_Web.woff2Gotham-Book_Web.woff2 https://www.bigcommerce.com/mm/fonts/Gotham-Book_Web.woff2 — 41.0 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/Gotham-BookItalic_Web.woff2Gotham-BookItalic_Web.w... https://www.bigcommerce.com/mm/fonts/Gotham-BookItalic_Web.woff2 — 43.6 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/Gotham-Light_Web.woff2Gotham-Light_Web.woff2 https://www.bigcommerce.com/mm/fonts/Gotham-Light_Web.woff2 — 39.7 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/Gotham-LightItalic_Web.woff2Gotham-LightItalic_Web.... https://www.bigcommerce.com/mm/fonts/Gotham-LightItalic_Web.woff2 — 40.8 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/Gotham-MediumItalic.otfGotham-MediumItalic.otf https://www.bigcommerce.com/mm/fonts/Gotham-MediumItalic.otf — 58.1 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/Gotham-BoldItalic.otfGotham-BoldItalic.otf https://www.bigcommerce.com/mm/fonts/Gotham-BoldItalic.otf — 54.4 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/Gotham-Medium_Web.woff2Gotham-Medium_Web.woff2 https://www.bigcommerce.com/mm/fonts/Gotham-Medium_Web.woff2 — 40.7 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/GothamCond-Bold_Web.woff2GothamCond-Bold_Web.woff2 https://www.bigcommerce.com/mm/fonts/GothamCond-Bold_Web.woff2 — 37.6 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/GothamCondensed-Medium.woff2GothamCondensed-Medium.... https://www.bigcommerce.com/mm/fonts/GothamCondensed-Medium.woff2 — 12.9 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/GeistMono/GeistMono-Light.ttfGeistMono-Light.ttf https://www.bigcommerce.com/mm/fonts/GeistMono/GeistMono-Light.ttf — 39.7 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/GeistMono/GeistMono-Regular.ttfGeistMono-Regular.ttf https://www.bigcommerce.com/mm/fonts/GeistMono/GeistMono-Regular.ttf — 38.9 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/GeistMono/GeistMono-Medium.ttfGeistMono-Medium.ttf https://www.bigcommerce.com/mm/fonts/GeistMono/GeistMono-Medium.ttf — 40.0 KiB — 0 ms — font-display: swaphttps://www.bigcommerce.com/mm/fonts/GeistMono/GeistMono-Bold.ttfGeistMono-Bold.ttf https://www.bigcommerce.com/mm/fonts/GeistMono/GeistMono-Bold.ttf — 40.3 KiB — 0 ms — font-display: swap
Gotham-Black_Web.woff2 woff2 swap
Size 41 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Gotham-Bold_Web.woff2 woff2 swap
Size 39 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Gotham-Book_Web.woff2 woff2 swap
Size 41 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Gotham-BookItalic_Web.w... woff2 swap
Size 44 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Gotham-Light_Web.woff2 woff2 swap
Size 40 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Gotham-LightItalic_Web.... woff2 swap
Size 41 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Gotham-MediumItalic.otf otf swap
Size 58 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Gotham-BoldItalic.otf otf swap
Size 54 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Gotham-Medium_Web.woff2 woff2 swap
Size 41 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
GothamCond-Bold_Web.woff2 woff2 swap
Size 38 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
GothamCondensed-Medium.... woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
GeistMono-Light.ttf ttf swap
Size 40 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
GeistMono-Regular.ttf ttf swap
Size 39 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
GeistMono-Medium.ttf ttf swap
Size 40 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
GeistMono-Bold.ttf ttf swap
Size 40 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
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 ~81 KB and ~162 ms

A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
Network Waterfall
154 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
9% of JavaScript execution is third-party
First-party Third-party 491ms · 0KB · $3/mo
Unattributable
Other
Costly
Execution 491ms
Transfer 0 KB
Monthly Cost $3/mo

These scripts may cost more than they're worth

  • Unattributable adds 491ms and costs ~$3/month

Unattributable takes 491ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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