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
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.
15 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.
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW
Green Hosting
No green hosting detected
A
Page Weight Budget
755 KB transferred, 52 requests
PASS
755 KB transferred, 52 requests
Info::
✓
Page weighs 2.3 MB (755 KB transferred)
Info::
i
Fonts are 201 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 201 KB
Info::
i
52 HTTP requests
Info::
i
Estimated 0.15 g CO2 per page load
755 KBtransferred
52 requests
0.15 g CO2 per page load
JavaScript487.9 KiB65%
Fonts201.3 KiB27%
HTML42.2 KiB6%
CSS10.7 KiB1%
Images5.3 KiB1%
Other4.0 KiB1%
Other2.1 KiB0%
Other1.1 KiB0%
Other673 B0%
02.4 MB4.9 MB
Under budget
Subset fonts to include only used characters, or switch to system font stacks.
Why this matters
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
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
2 fonts (201 KB)
PASS
2 fonts (201 KB)
Info::
i
2 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
2
201 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
6YirsaXqsap.woff2woff2swap
Size22 KB
Load time9 ms
Start1.2 s
RiskFOUT — text flashes from fallback to web font
-pkMfchyeAZ.woff2woff2swap
Size179 KB
Load time14 ms
Start1.2 s
RiskFOUT — text flashes from fallback to web font
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
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 ~90 KB and ~180 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
16 hints, 0 missing preconnects
PASS
16 hints, 0 missing preconnects
Info::
i
1 URL(s) appear in multiple hints
The same href shouldn't appear in multiple hint rels -- one wins, the others are wasted markup and may confuse cache behavior. Sample: https://static.xx.fbcdn.net/rsrc.php/v5/yn/l/0,cross/A1QZP0ChGIvg8T_6-Yirbb.css (preload+preload).
Info::
✓
Page uses 16 resource hint(s)
Current Resource Hints
preconnect
1
preload
+4
14
dns-prefetch
1
prefetch—
16 resource hints configured
The same href shouldn't appear in multiple hint rels -- one wins, the others are wasted markup and may confuse cache behavior. Sample: https://static.xx.fbcdn.net/rsrc.php/v5/yn/l/0,cross/A1QZP0ChGIvg8T_6-Yirbb.css (preload+preload).
Why this matters
Performance issues directly impact user engagement and conversion rates.
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
52 requests over 2401ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
80%of JavaScript execution is third-party
First-party Third-party2163ms · 450KB · $29/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
z-m-static.xx.fbcdn.net
z-m-static.xx.fbcdn.net
Other
884ms
257 KB
57%
$12/mo
Costly
z-m-static.xx.fbcdn.net
z-m-static.xx.fbcdn.net
Other
510ms
71 KB
48%
$7/mo
Costly
m.facebook.com
m.facebook.com
Other
445ms
42 KB
—
$6/mo
Costly
z-m-static.xx.fbcdn.net
z-m-static.xx.fbcdn.net
Other
138ms
13 KB
—
$2/mo
Optional
z-m-static.xx.fbcdn.net
z-m-static.xx.fbcdn.net
Other
95ms
52 KB
74%
$1/mo
Optional
z-m-static.xx.fbcdn.net
z-m-static.xx.fbcdn.net
Other
91ms
15 KB
—
$1/mo
Optional
z-m-static.xx.fbcdn.net
Other
Costly
Execution884ms
Transfer257 KB
Unused57%
Monthly Cost$12/mo
z-m-static.xx.fbcdn.net
Other
Costly
Execution510ms
Transfer71 KB
Unused48%
Monthly Cost$7/mo
m.facebook.com
Other
Costly
Execution445ms
Transfer42 KB
Monthly Cost$6/mo
z-m-static.xx.fbcdn.net
Other
Optional
Execution138ms
Transfer13 KB
Monthly Cost$2/mo
z-m-static.xx.fbcdn.net
Other
Optional
Execution95ms
Transfer52 KB
Unused74%
Monthly Cost$1/mo
z-m-static.xx.fbcdn.net
Other
Optional
Execution91ms
Transfer15 KB
Monthly Cost$1/mo
These scripts may cost more than they're worth
z-m-static.xx.fbcdn.net adds 884ms and costs ~$12/month
z-m-static.xx.fbcdn.net adds 510ms and costs ~$7/month
m.facebook.com adds 445ms and costs ~$6/month
80% 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
z-m-static.xx.fbcdn.net takes 884ms 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
57% of z-m-static.xx.fbcdn.net'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
z-m-static.xx.fbcdn.net takes 510ms 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
m.facebook.com takes 445ms 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
74% of z-m-static.xx.fbcdn.net'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.