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
22 images, 0 KB saveable
REVIEW
22 images, 0 KB saveable
Warning::
!
https://www.cynosure.com/wp-content/uploads/2024/0... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.cynosure.com/wp-content/themes/cynosur... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.cynosure.com/wp-content/themes/cynosur... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
22images1.4 MB
0oversized-0 KB
10legacy format
3missing 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
C
Compression Algorithm
Action
Main response served uncompressed
REVIEW
Main response served uncompressed
Info::
i
Main HTML response has no Content-Encoding (uncompressed)
The main HTML document is served without compression. The Text Compression section above lists the broader picture; for the main response specifically, even gzip would shave ~70-80% off most text payloads.
B
Main HTML Cache-Control
No Cache-Control header on main HTML response
REVIEW
No Cache-Control header on main HTML response
Info::
i
Main HTML response has no Cache-Control header
Without an explicit Cache-Control, browsers fall back to heuristic caching (~10% of Last-Modified age). Set `Cache-Control: no-cache` or `max-age=300` for HTML to control freshness explicitly -- prevents stale auth state and SPA shell drift.
B
Server-Timing Observability
No Server-Timing header found
REVIEW
No Server-Timing header found
Info::
i
No Server-Timing header found
Server-Timing exposes backend timing breakdowns to browser DevTools (e.g., `db: 45ms; render: 120ms; cache: 2ms`). Useful for diagnosing slow pages without backend log access. Most modern frameworks (Next.js, Cloudflare Workers, Fastly) emit it automatically; absence on a managed platform usually means telemetry headers are stripped at the edge.
B
JavaScript Blocking
2 JS blocking issue(s) detected
REVIEW
2 JS blocking issue(s) detected
Warning::
!
1 render-blocking <script src> tag(s) without async/defer
Each `<script src=...>` without `async`, `defer`, or `type="module"` blocks HTML parsing while the browser fetches and executes it. The block lasts the entire round-trip + execution time -- on slow networks this translates directly into LCP delay. Add `defer` (executes after parse, in source order) for scripts that interact with the DOM, or `async` (executes whenever ready) for analytics / independent scripts. Module scripts (`type="module"`) are deferred by default.
Warning::
!
Total JS execution time is 12.2 s -- over the 3.5s budget
Total JavaScript execution (parse + compile + run) across all scripts exceeds 3.5 seconds. On low-end devices that becomes 7-15+ seconds and shows up directly in TBT and INP. Reduce by: tree-shaking unused dependencies, code-splitting (dynamic `import()`), removing or deferring third-party tracking, and replacing heavy frameworks where they're not needed.
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
18 fonts (761 KB)
PASS
18 fonts (761 KB)
Info::
i
18 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
18
761 KB total
Render-blocking
0
of 18
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
Juana-Light.woff2woff2swap
Size34 KB
Load time84 ms
Start276 ms
RiskFOUT — text flashes from fallback to web font
Juana-LightIt.woff2woff2swap
Size34 KB
Load time83 ms
Start276 ms
RiskFOUT — text flashes from fallback to web font
Juana-Regular.woff2woff2swap
Size35 KB
Load time84 ms
Start277 ms
RiskFOUT — text flashes from fallback to web font
Juana-RegularIt.woff2woff2swap
Size35 KB
Load time38 ms
Start277 ms
RiskFOUT — text flashes from fallback to web font
Juana-Bold.woff2woff2swap
Size35 KB
Load time91 ms
Start278 ms
RiskFOUT — text flashes from fallback to web font
Juana-BoldIt.woff2woff2swap
Size35 KB
Load time91 ms
Start278 ms
RiskFOUT — text flashes from fallback to web font
Open_Sans_Light.woff2woff2swap
Size60 KB
Load time91 ms
Start279 ms
RiskFOUT — text flashes from fallback to web font
Open_Sans_Light_Italic....woff2swap
Size57 KB
Load time94 ms
Start279 ms
RiskFOUT — text flashes from fallback to web font
Open_Sans_Regular.woff2woff2swap
Size59 KB
Load time94 ms
Start279 ms
RiskFOUT — text flashes from fallback to web font
Open_Sans_Italic.woff2woff2swap
Size57 KB
Load time98 ms
Start281 ms
RiskFOUT — text flashes from fallback to web font
Open_Sans_Semibold.woff2woff2swap
Size60 KB
Load time102 ms
Start282 ms
RiskFOUT — text flashes from fallback to web font
Open_Sans_Semibold_Ital...woff2swap
Size58 KB
Load time102 ms
Start282 ms
RiskFOUT — text flashes from fallback to web font
Open_Sans_Bold.woff2woff2swap
Size61 KB
Load time99 ms
Start282 ms
RiskFOUT — text flashes from fallback to web font
Open_Sans_Bold_Italic.w...woff2swap
Size57 KB
Load time106 ms
Start283 ms
RiskFOUT — text flashes from fallback to web font
memvYaGs126MiZpBA-UvWbX...woff2swap
Size42 KB
Load time8 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
x-font-woff;charset=utf...woffswap
Size2 KB
Load time27 ms
Start2.0 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
x-font-woff;charset=utf...woffswap
Size8 KB
Load time13 ms
Start2.1 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
KFO7CnqEu92Fr1ME7kSn66a...woff2swap
Size34 KB
Load time37 ms
Start2.6 s
RiskFOUT — 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)
Fixing the unchecked items could save ~3 KB and ~6 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
A+
HTTP/3 (QUIC)
HTTP/3 advertised via Alt-Svc
PASS
HTTP/3 advertised via Alt-Svc
Info::
✓
HTTP/3 (QUIC) is supported
First-load mobile users on cellular networks see meaningful latency improvements with HTTP/3. The QUIC transport collapses TLS + TCP handshakes into one and recovers faster from packet loss.
A+
LCP Image Preload
LCP preload audit not available
PASS
LCP preload audit not available
Info::
✓
LCP image preload audit not available for this scan
A+
Server Response Intelligence
1 server-response signal(s) detected
PASS
1 server-response signal(s) detected
Info::
i
No `ETag` or `Last-Modified` -- conditional GET not supported
Without either header, browsers can't issue conditional GETs and refresh always re-downloads the full response body even when nothing changed. Add `ETag: "<hash>"` (or `Last-Modified: <date>`) on cacheable responses; the server returns 304 Not Modified when the client's cached copy is still valid, saving bandwidth.
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
✓
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A+
CSS Performance Depth
No CSS performance depth issues detected
PASS
No CSS performance depth issues detected
Info::
✓
No CSS performance depth issues detected
Network Waterfall
137 requests over 6338ms
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-party12247ms · 314KB · $163/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
fast.wistia.com
fast.wistia.com
Other
2052ms
160 KB
51%
$27/mo
Costly
www.cynosure.com
www.cynosure.com
Other
1942ms
0 KB
60%
$26/mo
Costly
Unattributable
Unattributable
Other
1574ms
0 KB
—
$21/mo
Costly
fast.wistia.com
fast.wistia.com
Other
1546ms
0 KB
44%
$21/mo
Costly
www.gstatic.com
www.gstatic.com
Other
1342ms
0 KB
48%
$18/mo
Costly
ssl-munchkin.marketo.net
ssl-munchkin.marketo.net
Other
1220ms
0 KB
—
$16/mo
Costly
fast.wistia.com
fast.wistia.com
Other
951ms
0 KB
81%
$13/mo
Costly
consent.cookiebot.com
consent.cookiebot.com
Other
908ms
27 KB
—
$12/mo
Costly
www.cynosure.com
www.cynosure.com
Other
555ms
18 KB
—
$7/mo
Costly
consent.cookiebot.com
consent.cookiebot.com
Other
89ms
110 KB
24%
$1/mo
Optional
www.cynosure.com
www.cynosure.com
Other
68ms
0 KB
—
$1/mo
Optional
fast.wistia.com
Other
Costly
Execution2052ms
Transfer160 KB
Unused51%
Monthly Cost$27/mo
www.cynosure.com
Other
Costly
Execution1942ms
Transfer0 KB
Unused60%
Monthly Cost$26/mo
Unattributable
Other
Costly
Execution1574ms
Transfer0 KB
Monthly Cost$21/mo
fast.wistia.com
Other
Costly
Execution1546ms
Transfer0 KB
Unused44%
Monthly Cost$21/mo
www.gstatic.com
Other
Costly
Execution1342ms
Transfer0 KB
Unused48%
Monthly Cost$18/mo
ssl-munchkin.marketo.net
Other
Costly
Execution1220ms
Transfer0 KB
Monthly Cost$16/mo
fast.wistia.com
Other
Costly
Execution951ms
Transfer0 KB
Unused81%
Monthly Cost$13/mo
consent.cookiebot.com
Other
Costly
Execution908ms
Transfer27 KB
Monthly Cost$12/mo
www.cynosure.com
Other
Costly
Execution555ms
Transfer18 KB
Monthly Cost$7/mo
consent.cookiebot.com
Other
Optional
Execution89ms
Transfer110 KB
Unused24%
Monthly Cost$1/mo
www.cynosure.com
Other
Optional
Execution68ms
Transfer0 KB
Monthly Cost$1/mo
These scripts may cost more than they're worth
fast.wistia.com adds 2052ms and costs ~$27/month
www.cynosure.com adds 1942ms and costs ~$26/month
Unattributable adds 1574ms and costs ~$21/month
fast.wistia.com adds 1546ms and costs ~$21/month
www.gstatic.com adds 1342ms and costs ~$18/month
ssl-munchkin.marketo.net adds 1220ms and costs ~$16/month
fast.wistia.com adds 951ms and costs ~$13/month
consent.cookiebot.com adds 908ms and costs ~$12/month
www.cynosure.com adds 555ms and costs ~$7/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
fast.wistia.com takes 2052ms 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
51% of fast.wistia.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
www.cynosure.com takes 1942ms 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.cynosure.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
Unattributable takes 1574ms 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
fast.wistia.com takes 1546ms 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.gstatic.com takes 1342ms 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
ssl-munchkin.marketo.net takes 1220ms 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
fast.wistia.com takes 951ms 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
81% of fast.wistia.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
consent.cookiebot.com takes 908ms 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.cynosure.com takes 555ms 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.