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
36 images, 0 KB saveable
REVIEW
36 images, 0 KB saveable
Warning::
!
https://www.fjackets.com/images/fjackets-d-logo.we... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.fjackets.com/images/homebanner/sec_8_i... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
36images973 KB
0oversized-0 KB
10legacy format
2missing 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
B
HTTP/3 (QUIC)
HTTP/3 not advertised
REVIEW
HTTP/3 not advertised
Info::
i
HTTP/3 (QUIC) is not advertised
HTTP/3 isn't advertised via Alt-Svc and the worker didn't negotiate h3. HTTP/3 reduces handshake latency (1-RTT instead of 2-3 RTTs) and is more resilient on lossy connections. Most modern CDNs (Cloudflare, Fastly, AWS CloudFront, Google Cloud CDN) support HTTP/3 with a single config switch -- consider enabling for mobile-heavy workloads.
C
Document Compression
Action
Document response served uncompressed
REVIEW
Document 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
Asset Compression
1 of 5 asset hosts serve text uncompressed
REVIEW
1 of 5 asset hosts serve text uncompressed
Warning::
!
www.fjackets.com serves text assets uncompressed (assets: 78)
The sampled response carries a text content type but no Content-Encoding, so the bytes go over the wire raw. Text compression typically removes 70-80% of a JS or CSS payload -- this is the single cheapest transfer win available on this host.
Got: www.fjackets.com (text/html)
Info::
✓
static.klaviyo.com serves assets with brotli (assets: 9)
Got: static.klaviyo.com (text/javascript)
Info::
✓
static-tracking.klaviyo.com serves assets with brotli (assets: 4)
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::
!
3 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 5.7 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.
Each `<link rel="stylesheet">` without a non-blocking `media` attribute holds up the first paint. Browsers download all of them before painting any content. Consolidate into 1-2 critical-path stylesheets; defer non-critical CSS via `<link rel="stylesheet" media="print" onload="this.media='all'">` or via the loadCSS pattern; inline above-the-fold CSS in `<style>` to short-circuit the request entirely.
Info::
i
1 `@import` rule(s) in inline `<style>` blocks -- chains an extra round-trip
Each `@import` in CSS forces a serial dependency: the parent stylesheet must download and parse before the browser even knows which URL to fetch next. This used to be catastrophic on HTTP/1.1; HTTP/2 and HTTP/3 multiplexing make it less painful but still strictly worse than declaring `<link rel="stylesheet">` siblings. Replace `@import url(...)` with `<link rel="stylesheet" href="...">` in HTML so the browser discovers and fetches in parallel.
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
8 fonts (149 KB)
PASS
8 fonts (149 KB)
Info::
i
8 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
8
149 KB total
Render-blocking
0
of 8
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
pxiEyp8kv8JHgFVrJJfecg....woff2swap
Size8 KB
Load time23 ms
Start551 ms
RiskFOUT — text flashes from fallback to web font
QGYsz_wNahGAdqQ43Rh_fKD...woff2swap
Size49 KB
Load time58 ms
Start697 ms
RiskFOUT — text flashes from fallback to web font
TK3IWkUHHAIjg75cFRf3bXL...woff2swap
Size21 KB
Load time35 ms
Start799 ms
RiskFOUT — text flashes from fallback to web font
3y9H6as8bTXq_nANBjzKo3I...woff2swap
Size40 KB
Load time49 ms
Start801 ms
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLGT9Z1x...woff2swap
Size8 KB
Load time33 ms
Start2.4 s
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLCz7Z1x...woff2swap
Size8 KB
Load time37 ms
Start2.4 s
RiskFOUT — text flashes from fallback to web font
pxiEyp8kv8JHgFVrJJfecnF...woff2swap
Size8 KB
Load time36 ms
Start2.4 s
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLEj6Z1x...woff2swap
Size8 KB
Load time33 ms
Start2.4 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)
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
3 hints, 0 missing preconnects
PASS
3 hints, 0 missing preconnects
Info::
✓
Page uses 3 resource hint(s)
Current Resource Hints
preconnect
2
preload
1
dns-prefetch—
prefetch—
3 resource hints configured
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+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Google Cloud
Network Waterfall
157 requests over 5739ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
84%of JavaScript execution is third-party
First-party Third-party4816ms · 1115KB · $28/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.fjackets.com
www.fjackets.com
Other
1421ms
64 KB
—
$8/mo
Costly
us-server.fjackets.com
us-server.fjackets.com
Other
737ms
161 KB
37%
$4/mo
Costly
us-server.fjackets.com
us-server.fjackets.com
Other
441ms
165 KB
38%
$3/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
365ms
182 KB
25%
$2/mo
Costly
us-server.fjackets.com
us-server.fjackets.com
Other
351ms
150 KB
39%
$2/mo
Costly
static.klaviyo.com
static.klaviyo.com
Other
302ms
68 KB
82%
$2/mo
Costly
Microsoft Clarity
scripts.clarity.ms
Session Replay
225ms
25 KB
—
$1/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
216ms
112 KB
33%
$1/mo
Costly
www.fjackets.com
www.fjackets.com
Other
166ms
34 KB
—
$1/mo
Optional
static.klaviyo.com
static.klaviyo.com
Other
150ms
16 KB
—
$1/mo
Optional
b-code.liadm.com
b-code.liadm.com
Other
131ms
58 KB
39%
$1/mo
Optional
static.klaviyo.com
static.klaviyo.com
Other
84ms
9 KB
—
$0/mo
Optional
s.pinimg.com
s.pinimg.com
Other
83ms
38 KB
55%
$0/mo
Optional
static.klaviyo.com
static.klaviyo.com
Other
82ms
7 KB
—
$0/mo
Optional
static.klaviyo.com
static.klaviyo.com
Other
61ms
26 KB
—
$0/mo
Optional
www.fjackets.com
Other
Costly
Execution1421ms
Transfer64 KB
Monthly Cost$8/mo
us-server.fjackets.com
Other
Costly
Execution737ms
Transfer161 KB
Unused37%
Monthly Cost$4/mo
us-server.fjackets.com
Other
Costly
Execution441ms
Transfer165 KB
Unused38%
Monthly Cost$3/mo
Facebook Pixel
Advertising
Costly
Execution365ms
Transfer182 KB
Unused25%
Monthly Cost$2/mo
us-server.fjackets.com
Other
Costly
Execution351ms
Transfer150 KB
Unused39%
Monthly Cost$2/mo
static.klaviyo.com
Other
Costly
Execution302ms
Transfer68 KB
Unused82%
Monthly Cost$2/mo
Microsoft Clarity
Session Replay
Costly
Execution225ms
Transfer25 KB
Monthly Cost$1/mo
Facebook Pixel
Advertising
Costly
Execution216ms
Transfer112 KB
Unused33%
Monthly Cost$1/mo
www.fjackets.com
Other
Optional
Execution166ms
Transfer34 KB
Monthly Cost$1/mo
static.klaviyo.com
Other
Optional
Execution150ms
Transfer16 KB
Monthly Cost$1/mo
b-code.liadm.com
Other
Optional
Execution131ms
Transfer58 KB
Unused39%
Monthly Cost$1/mo
static.klaviyo.com
Other
Optional
Execution84ms
Transfer9 KB
Monthly Cost$0/mo
s.pinimg.com
Other
Optional
Execution83ms
Transfer38 KB
Unused55%
Monthly Cost$0/mo
static.klaviyo.com
Other
Optional
Execution82ms
Transfer7 KB
Monthly Cost$0/mo
static.klaviyo.com
Other
Optional
Execution61ms
Transfer26 KB
Monthly Cost$0/mo
These scripts may cost more than they're worth
www.fjackets.com adds 1421ms and costs ~$8/month
us-server.fjackets.com adds 737ms and costs ~$4/month
us-server.fjackets.com adds 441ms and costs ~$3/month
Facebook Pixel adds 365ms and costs ~$2/month
us-server.fjackets.com adds 351ms and costs ~$2/month
static.klaviyo.com adds 302ms and costs ~$2/month
Microsoft Clarity adds 225ms and costs ~$1/month
Facebook Pixel adds 216ms and costs ~$1/month
84% 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
www.fjackets.com takes 1421ms 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
us-server.fjackets.com takes 737ms 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
us-server.fjackets.com takes 441ms 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
Facebook Pixel takes 365ms 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
us-server.fjackets.com takes 351ms 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
static.klaviyo.com takes 302ms 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
82% of static.klaviyo.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
Microsoft Clarity takes 225ms 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
Facebook Pixel takes 216ms 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
55% of s.pinimg.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.