Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
C
Image Optimization
Action
57 images, 0 KB saveable
REVIEW
57 images, 0 KB saveable
Warning::
!
https://www.subway.com/en-us/-/media/project/remot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/northamerica/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a63... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3aba... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a7b... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/northamerica/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3abc... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/project/remot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/Assets/RemoteOrder/img/shar... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3ab0... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3acb... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/Assets/RemoteOrder/img/clos... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/northamerica/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a61... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a4a... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/northamerica/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/northamerica/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a49... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/project/remot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/northamerica/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/Assets/RemoteOrder/img/clos... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3ac9... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a1a... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a91... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/northamerica/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a74... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a8e... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/northamerica/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/northamerica/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3aaf... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3ae9... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a5e... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/project/remot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://media.subway.com/dam/urn%3aaaid%3aaem%3a32... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/project/remot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.subway.com/en-us/-/media/project/remot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
57images777 KB
0oversized-0 KB
45legacy format
36missing dimensionsCLS 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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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+
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
12 fonts (752 KB)
PASS
12 fonts (752 KB)
Info::
i
12 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
12
752 KB total
Render-blocking
0
of 12
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
SubwaySans-Regular-Cy-G...woff2swap
Size49 KB
Load time33 ms
Start873 ms
RiskFOUT — text flashes from fallback to web font
font-woff;charset=utf-8...woffswap
Size2 KB
Load time273 ms
Start953 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
SubwaySansCond-Medium.woffwoffswap
Size86 KB
Load time30 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
SubwaySansLCG-Regular.woffwoffswap
Size113 KB
Load time37 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
SubwaySansLCG-Bold.woffwoffswap
Size117 KB
Load time40 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
SubwaySansCond-Medium-W...woff2swap
Size36 KB
Load time21 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a...woff2swap
Size37 KB
Load time7 ms
Start1.2 s
RiskFOUT — text flashes from fallback to web font
SubwaySansLCG-Medium.woffwoffswap
Size117 KB
Load time27 ms
Start1.2 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
SubwaySans-Bold-Cy-Gr-W...woff2swap
Size54 KB
Load time16 ms
Start1.4 s
RiskFOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a...woff2swap
Size0 KB
Load time0 ms
Start2.7 s
RiskFOUT — text flashes from fallback to web font
SubwaySans-Medium-Cy-Gr...woff2swap
Size54 KB
Load time19 ms
Start2.7 s
RiskFOUT — text flashes from fallback to web font
SubwaySansCond-Bold.woffwoffswap
Size87 KB
Load time86 ms
Start3.0 s
RiskFOUT — 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 ~330 KB and ~660 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
186 requests over 6484ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100%of JavaScript execution is third-party
First-party Third-party2556ms · 1319KB · $34/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
Unattributable
Unattributable
Other
516ms
0 KB
—
$7/mo
Costly
www.subway.com
www.subway.com
Other
448ms
24 KB
—
$6/mo
Costly
www.subway.com
www.subway.com
Other
344ms
341 KB
63%
$5/mo
Costly
cdn.quantummetric.com
cdn.quantummetric.com
Other
287ms
101 KB
35%
$4/mo
Costly
www.subway.com
www.subway.com
Other
259ms
1 KB
21%
$3/mo
Costly
assets.adobedtm.com
assets.adobedtm.com
Other
199ms
262 KB
35%
$3/mo
Optional
www.subway.com
www.subway.com
Other
150ms
334 KB
60%
$2/mo
Optional
OneTrust
cdn.cookielaw.org
Consent
123ms
127 KB
53%
$2/mo
Essential
www.subway.com
www.subway.com
Other
94ms
41 KB
—
$1/mo
Optional
js-cdn.dynatrace.com
js-cdn.dynatrace.com
Other
86ms
79 KB
36%
$1/mo
Optional
www.subway.com
www.subway.com
Other
50ms
9 KB
—
$1/mo
Optional
Unattributable
Other
Costly
Execution516ms
Transfer0 KB
Monthly Cost$7/mo
www.subway.com
Other
Costly
Execution448ms
Transfer24 KB
Monthly Cost$6/mo
www.subway.com
Other
Costly
Execution344ms
Transfer341 KB
Unused63%
Monthly Cost$5/mo
cdn.quantummetric.com
Other
Costly
Execution287ms
Transfer101 KB
Unused35%
Monthly Cost$4/mo
www.subway.com
Other
Costly
Execution259ms
Transfer1 KB
Unused21%
Monthly Cost$3/mo
assets.adobedtm.com
Other
Optional
Execution199ms
Transfer262 KB
Unused35%
Monthly Cost$3/mo
www.subway.com
Other
Optional
Execution150ms
Transfer334 KB
Unused60%
Monthly Cost$2/mo
OneTrust
Consent
Essential
Execution123ms
Transfer127 KB
Unused53%
Monthly Cost$2/mo
www.subway.com
Other
Optional
Execution94ms
Transfer41 KB
Monthly Cost$1/mo
js-cdn.dynatrace.com
Other
Optional
Execution86ms
Transfer79 KB
Unused36%
Monthly Cost$1/mo
www.subway.com
Other
Optional
Execution50ms
Transfer9 KB
Monthly Cost$1/mo
These scripts may cost more than they're worth
Unattributable adds 516ms and costs ~$7/month
www.subway.com adds 448ms and costs ~$6/month
www.subway.com adds 344ms and costs ~$5/month
cdn.quantummetric.com adds 287ms and costs ~$4/month
www.subway.com adds 259ms and costs ~$3/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
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
Unattributable takes 516ms 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
www.subway.com takes 448ms 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
www.subway.com takes 344ms 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
63% of www.subway.com'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
cdn.quantummetric.com takes 287ms 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
www.subway.com takes 259ms 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
60% of www.subway.com'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
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.
846 ms
2.5 s
3.4 s
4.2 s
5.9 s
6.8 s