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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
4
REVIEW
2
PASS
6
INFO
2

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

Mobile Desktop
36
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
93
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
83
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.

1.80 s

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

4.30 s

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

868 ms

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

0.040

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

3.32 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.

5.06 s

Page Load Progression

679 ms
1.4 s
2.0 s
2.7 s
3.4 s
4.1 s
4.8 s
5.4 s
Checks
14
6 PASS 2 REVIEW 4 FIX
F
Page Weight Budget
Action
3.3 MB transferred, 201 requests
FIX
3.3 MB transferred, 201 requests
Warning::
Page weighs 15.2 MB (3.3 MB transferred)
Warning::
JavaScript is 1.8 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.8 MB
Warning::
201 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.68 g CO2 per page load
3.3 MB / 2.4 MB budget
3.3 MB transferred
201 requests
0.68 g CO2 per page load
JavaScript 1.8 MiB 57%
Images 919.7 KiB 28%
Other 248.9 KiB 7%
Fonts 129.5 KiB 4%
CSS 64.0 KiB 2%
Other 50.9 KiB 2%
Other 24.0 KiB 1%
HTML 15.1 KiB 0%
Other 0 B 0%
Other 0 B 0%
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

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
5319ms total JS execution
FIX
5319ms total JS execution
Warning::
https://www.delta.com/homepage/26.3.8/mach-core/br...: 1224ms CPU time
Warning::
https://www.delta.com/resources/df032bb95163120c0d...: 1044ms CPU time
Warning::
Unattributable: 843ms CPU time
Warning::
https://www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7...: 448ms CPU time
Warning::
https://www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/wb7...: 376ms CPU time
Info::
Third-party scripts: 1562ms (29% of total)

Main Thread Breakdown

Script Evaluation 65% Other 16% Script Parsing & Compilation 9% Style & Layout 5%
ScriptTotalScriptingParse/CompileParty
https://www.delta.com/homepage/26.3.8/mach-core/browser/polyfills.js1224ms1011ms2ms1st
https://www.delta.com/resources/df032bb95163120c0d0265eb98f27f913a30d77a1d98e1044ms896ms33ms1st
Unattributable843ms194ms0ms3rd
https://www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB448ms383ms45ms1st
https://www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/wb7hbLaQ/K0ciPAE/UHQfJX/dcDxdt?v=c25fdc53-9bc7-8767-c05d-4eb57f670210376ms290ms77ms1st
https://www.delta.com/eu/en368ms5ms2ms1st
https://tms.delta.com/delta/dl_anderson/Bootstrap.js346ms274ms54ms3rd
https://assets.adobedtm.com/3b29aa0834b1/0e49b4a4297a/launch-ab7c06f028a9.min.js237ms172ms55ms3rd
https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js171ms3ms167ms1st
https://cdn.cookielaw.org/scripttemplates/202503.1.0/otBannerSdk.js136ms92ms19ms3rd

Showing top 10 of 12 scripts

F
JS Bundles
Action
57 scripts, 1.2 MB unused
FIX
57 scripts, 1.2 MB unused
Warning::
https://www.delta.com/homepage/26.3.8/mach-core/br...: 342 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.delta.com/homepage/26.3.8/mach-core/br...: 342 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.cookielaw.org/scripttemplates/202503.1...: 62 KB unused (53%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://tms.delta.com/delta/dl_anderson/Bootstrap....: 45 KB unused (47%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://tms.delta.com/delta/dl_anderson/Bootstrap....: 45 KB unused (47%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 1.2 MB
1207 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js0 KB342 KB (52%)✓1st
https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js662 KB342 KB (52%)✓1st
https://cdn.cookielaw.org/scripttemplates/202503.1.0/otBannerSdk.js116 KB62 KB (53%)✓3rd
https://tms.delta.com/delta/dl_anderson/Bootstrap.js96 KB45 KB (47%)✓3rd
https://tms.delta.com/delta/dl_anderson/Bootstrap.js0 KB45 KB (47%)✓3rd
https://assets.adobedtm.com/3b29aa0834b1/0e49b4a4297a/launch-ab7c06f028a9.min.js100 KB37 KB (37%)✓3rd
https://assets.adobedtm.com/3b29aa0834b1/0e49b4a4297a/launch-ab7c06f028a9.min.js0 KB37 KB (37%)✓3rd
https://www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB173 KB36 KB (21%)✓1st
https://www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB173 KB36 KB (21%)✓1st
https://www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/wb7hbLaQ/K0ciPAE/UHQfJX/dcDxdt?v=c25fdc53-9bc7-8767-c05d-4eb57f6702100 KB34 KB (21%)✓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

D
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

B
Image Optimization
49 images, 0 KB saveable
REVIEW
49 images, 0 KB saveable
Warning::
https://www.delta.com/content/dam/delta-applicatio... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
49 images 283 KB
0 oversized -0 KB
16 legacy format
1 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Third-Party Impact
18% third-party, 0 ms blocking
PASS
18% third-party, 0 ms blocking
Info::
Third-party code accounts for 18% of page weight (589.9 KiB of 3.3 MiB)
Info::
Third-party blocking time is low (0 ms)
82%
18%
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 (129 KB)
PASS
15 fonts (129 KB)
Info::
15 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

15

129 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 1.0 s 2.0 s 3.0 s 4.0 s FCP 1.8 s LCP 4.3 shttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/CB8837CA379681FED.woff2CB8837CA379681FED.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/CB8837CA379681FED.woff2 — 13.0 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/AABA9C13AF9C5C638.woff2AABA9C13AF9C5C638.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/AABA9C13AF9C5C638.woff2 — 12.8 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/3955045D2CF71A4B6.woff23955045D2CF71A4B6.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/3955045D2CF71A4B6.woff2 — 13.0 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/whitney-condensed.woff2whitney-condensed.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/whitney-condensed.woff2 — 13.3 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/A32A3E152E391B379.woff2A32A3E152E391B379.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/A32A3E152E391B379.woff2 — 12.8 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/3955045D2CF71A4B6.woff23955045D2CF71A4B6.woff2 https://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/3955045D2CF71A4B6.woff2 — 12.8 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/5F3C862F467F43533.woff25F3C862F467F43533.woff2 https://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/5F3C862F467F43533.woff2 — 12.9 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/AABA9C13AF9C5C638.woff2AABA9C13AF9C5C638.woff2 https://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/AABA9C13AF9C5C638.woff2 — 12.6 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/C2031C89118431E67.woff2C2031C89118431E67.woff2 https://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/C2031C89118431E67.woff2 — 13.3 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/CB8837CA379681FED.woff2CB8837CA379681FED.woff2 https://www.delta.com/content/dam/delta-applications/fresh-air-core/general/fonts/CB8837CA379681FED.woff2 — 12.9 KiB — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/CB8837CA379681FED.woff2CB8837CA379681FED.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/CB8837CA379681FED.woff2 — 0 B — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/AABA9C13AF9C5C638.woff2AABA9C13AF9C5C638.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/AABA9C13AF9C5C638.woff2 — 0 B — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/3955045D2CF71A4B6.woff23955045D2CF71A4B6.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/3955045D2CF71A4B6.woff2 — 0 B — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/A32A3E152E391B379.woff2A32A3E152E391B379.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/A32A3E152E391B379.woff2 — 0 B — 0 ms — font-display: swaphttps://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/whitney-condensed.woff2whitney-condensed.woff2 https://www.delta.com/content/dam/delta-applications/mach-1/assets/fonts/whitney-condensed.woff2 — 0 B — 0 ms — font-display: swap
CB8837CA379681FED.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
AABA9C13AF9C5C638.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
3955045D2CF71A4B6.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
whitney-condensed.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
A32A3E152E391B379.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
3955045D2CF71A4B6.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
5F3C862F467F43533.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
AABA9C13AF9C5C638.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
C2031C89118431E67.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
CB8837CA379681FED.woff2 woff2 swap
Size 13 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
CB8837CA379681FED.woff2 woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
AABA9C13AF9C5C638.woff2 woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
3955045D2CF71A4B6.woff2 woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
A32A3E152E391B379.woff2 woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
whitney-condensed.woff2 woff2 swap
Size 0 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
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 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
201 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
29% of JavaScript execution is third-party
First-party Third-party 1562ms · 116KB · $21/mo
Unattributable
Other
Costly
Execution 843ms
Transfer 0 KB
Monthly Cost $11/mo
tms.delta.com
Other
Costly
Execution 346ms
Transfer 0 KB
Unused 47%
Monthly Cost $5/mo
assets.adobedtm.com
Other
Costly
Execution 237ms
Transfer 0 KB
Unused 37%
Monthly Cost $3/mo
OneTrust
Consent
Essential
Execution 136ms
Transfer 116 KB
Unused 53%
Monthly Cost $2/mo

These scripts may cost more than they're worth

  • Unattributable adds 843ms and costs ~$11/month
  • tms.delta.com adds 346ms and costs ~$5/month
  • assets.adobedtm.com adds 237ms and costs ~$3/month

Unattributable takes 843ms 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

tms.delta.com takes 346ms 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

assets.adobedtm.com takes 237ms 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

53% of OneTrust's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

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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