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.
B
Page Weight Budget
1.3 MB transferred, 49 requests
REVIEW
1.3 MB transferred, 49 requests
Info::
✓
Page weighs 4.4 MB (1.3 MB transferred)
Warning::
!
JavaScript is 1.1 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.1 MB
Info::
✓
49 HTTP requests
Info::
i
Estimated 0.28 g CO2 per page load
1.3 MBtransferred
49 requests
0.28 g CO2 per page load
JavaScript1.1 MiB83%
Fonts136.7 KiB10%
CSS60.8 KiB4%
HTML30.5 KiB2%
Images3.9 KiB0%
Other2.8 KiB0%
Other837 B0%
Other556 B0%
Other168 B0%
02.4 MB4.9 MB
Under 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
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 3.6 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+
Image Optimization
2 images, 0 KB saveable
PASS
2 images, 0 KB saveable
Info::
✓
All images are well-optimized
2images4 KB
0oversized-0 KB
1legacy format
0missing dimensionsCLS risk
A+
Font Loading
5 fonts (137 KB)
PASS
5 fonts (137 KB)
Info::
i
5 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
5
137 KB total
Render-blocking
0
of 5
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
memvYaGs126MiZpBA-UvWbX...woff2swap
Size42 KB
Load time123 ms
Start458 ms
RiskFOUT — text flashes from fallback to web font
memvYaGs126MiZpBA-UvWbX...woff2swap
Size22 KB
Load time107 ms
Start458 ms
RiskFOUT — text flashes from fallback to web font
ET-Extra.woffwoffswap
Size10 KB
Load time295 ms
Start628 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
memvYaGs126MiZpBA-UvWbX...woff2swap
Size42 KB
Load time46 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
memvYaGs126MiZpBA-UvWbX...woff2swap
Size21 KB
Load time49 ms
Start1.1 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
4 hints, 0 missing preconnects
PASS
4 hints, 0 missing preconnects
Info::
✓
Page uses 4 resource hint(s)
Current Resource Hints
preconnect—
preload—
dns-prefetch
4
prefetch—
4 resource hints configured
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+
Compression Algorithm
Main response uses brotli
PASS
Main response uses brotli
Info::
✓
Main HTML response uses brotli (Content-Encoding: br)
Brotli is the best text-compression algorithm for general use, ~20% smaller than gzip on average (40% on smaller files). Modern browsers all support it.
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
2 server-response signal(s) detected
PASS
2 server-response signal(s) detected
Info::
✓
`Vary` header declared: accept-encoding
The page declares a `Vary` header, telling downstream caches which request headers the response varies on. Critical for content-negotiated responses (compression, language, cookies, device class).
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.
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.
Network Waterfall
49 requests over 1509ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
49%of JavaScript execution is third-party
First-party Third-party1769ms · 927KB · $10/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
fundingchoicesmessages.google.com
fundingchoicesmessages.google.com
Other
458ms
70 KB
—
$3/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
330ms
163 KB
41%
$2/mo
Costly
fundingchoicesmessages.google.com
fundingchoicesmessages.google.com
Other
267ms
70 KB
51%
$2/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
173ms
121 KB
49%
$1/mo
Optional
pagead2.googlesyndication.com
pagead2.googlesyndication.com
Other
148ms
56 KB
38%
$1/mo
Optional
pagead2.googlesyndication.com
pagead2.googlesyndication.com
Other
145ms
166 KB
83%
$1/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
124ms
163 KB
69%
$1/mo
Optional
accounts.google.com
accounts.google.com
Other
66ms
97 KB
78%
$0/mo
Optional
Google Analytics
www.google-analytics.com
Analytics
57ms
21 KB
—
$0/mo
Optional
fundingchoicesmessages.google.com
Other
Costly
Execution458ms
Transfer70 KB
Monthly Cost$3/mo
Google Tag Manager
Tag Manager
Costly
Execution330ms
Transfer163 KB
Unused41%
Monthly Cost$2/mo
fundingchoicesmessages.google.com
Other
Costly
Execution267ms
Transfer70 KB
Unused51%
Monthly Cost$2/mo
Google Tag Manager
Tag Manager
Optional
Execution173ms
Transfer121 KB
Unused49%
Monthly Cost$1/mo
pagead2.googlesyndication.com
Other
Optional
Execution148ms
Transfer56 KB
Unused38%
Monthly Cost$1/mo
pagead2.googlesyndication.com
Other
Optional
Execution145ms
Transfer166 KB
Unused83%
Monthly Cost$1/mo
Google Tag Manager
Tag Manager
Optional
Execution124ms
Transfer163 KB
Unused69%
Monthly Cost$1/mo
accounts.google.com
Other
Optional
Execution66ms
Transfer97 KB
Unused78%
Monthly Cost$0/mo
Google Analytics
Analytics
Optional
Execution57ms
Transfer21 KB
Monthly Cost$0/mo
These scripts may cost more than they're worth
fundingchoicesmessages.google.com adds 458ms and costs ~$3/month
Google Tag Manager adds 330ms and costs ~$2/month
fundingchoicesmessages.google.com adds 267ms and costs ~$2/month
49% of JavaScript execution time comes from third-party scripts.
Why this matters
Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.
Learn more ▾▴
Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.
Source: web.dev / HTTP Archive Web Almanac
fundingchoicesmessages.google.com takes 458ms 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
Google Tag Manager takes 330ms 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
fundingchoicesmessages.google.com takes 267ms 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 fundingchoicesmessages.google.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
83% of pagead2.googlesyndication.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
69% of Google Tag Manager'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
78% of accounts.google.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.