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
Image Optimization
22 images, 0 KB saveable
REVIEW
22 images, 0 KB saveable
Info::
✓
All images are well-optimized
22images646 KB
0oversized-0 KB
12legacy format
0missing dimensionsCLS risk
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
9 fonts (191 KB)
PASS
9 fonts (191 KB)
Info::
i
9 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
9
191 KB total
Render-blocking
0
of 9
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
lwoff2swap
Size18 KB
Load time29 ms
Start516 ms
RiskFOUT — text flashes from fallback to web font
lwoff2swap
Size18 KB
Load time30 ms
Start519 ms
RiskFOUT — text flashes from fallback to web font
lwoff2swap
Size17 KB
Load time31 ms
Start519 ms
RiskFOUT — text flashes from fallback to web font
lwoff2swap
Size17 KB
Load time34 ms
Start519 ms
RiskFOUT — text flashes from fallback to web font
29D59A_0_0.woffwoffswap
Size36 KB
Load time20 ms
Start762 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
lwoff2swap
Size14 KB
Load time19 ms
Start762 ms
RiskFOUT — text flashes from fallback to web font
lwoff2swap
Size19 KB
Load time17 ms
Start762 ms
RiskFOUT — text flashes from fallback to web font
lwoff2swap
Size15 KB
Load time6 ms
Start909 ms
RiskFOUT — text flashes from fallback to web font
29D59A_1_0.woffwoffswap
Size37 KB
Load time13 ms
Start1.5 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 ~22 KB and ~44 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
12 hints, 0 missing preconnects
PASS
12 hints, 0 missing preconnects
Info::
✓
Page uses 12 resource hint(s)
Current Resource Hints
preconnect
5
preload
7
dns-prefetch—
prefetch—
12 resource hints configured
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: Cloudflare
Network Waterfall
50 requests over 2061ms
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-party4342ms · 1271KB · €47/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.edutopia.org
www.edutopia.org
Other
1550ms
571 KB
58%
€17/mo
Costly
www.edutopia.org
www.edutopia.org
Other
769ms
37 KB
—
€8/mo
Costly
www.edutopia.org
www.edutopia.org
Other
528ms
44 KB
—
€6/mo
Costly
Unattributable
Unattributable
Other
518ms
0 KB
—
€6/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
284ms
173 KB
41%
€3/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
174ms
45 KB
—
€2/mo
Optional
Facebook Pixel
connect.facebook.net
Advertising
173ms
97 KB
35%
€2/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
133ms
112 KB
63%
€1/mo
Optional
cdn.parsely.com
cdn.parsely.com
Other
113ms
19 KB
—
€1/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
99ms
173 KB
67%
€1/mo
Optional
www.edutopia.org
Other
Costly
Execution1550ms
Transfer571 KB
Unused58%
Monthly Cost€17/mo
www.edutopia.org
Other
Costly
Execution769ms
Transfer37 KB
Monthly Cost€8/mo
www.edutopia.org
Other
Costly
Execution528ms
Transfer44 KB
Monthly Cost€6/mo
Unattributable
Other
Costly
Execution518ms
Transfer0 KB
Monthly Cost€6/mo
Google Tag Manager
Tag Manager
Costly
Execution284ms
Transfer173 KB
Unused41%
Monthly Cost€3/mo
Facebook Pixel
Advertising
Optional
Execution174ms
Transfer45 KB
Monthly Cost€2/mo
Facebook Pixel
Advertising
Optional
Execution173ms
Transfer97 KB
Unused35%
Monthly Cost€2/mo
Google Tag Manager
Tag Manager
Optional
Execution133ms
Transfer112 KB
Unused63%
Monthly Cost€1/mo
cdn.parsely.com
Other
Optional
Execution113ms
Transfer19 KB
Monthly Cost€1/mo
Google Tag Manager
Tag Manager
Optional
Execution99ms
Transfer173 KB
Unused67%
Monthly Cost€1/mo
These scripts may cost more than they're worth
www.edutopia.org adds 1550ms and costs ~€17/month
www.edutopia.org adds 769ms and costs ~€8/month
www.edutopia.org adds 528ms and costs ~€6/month
Unattributable adds 518ms and costs ~€6/month
Google Tag Manager adds 284ms 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
www.edutopia.org takes 1550ms 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
58% of www.edutopia.org'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.edutopia.org takes 769ms 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.edutopia.org takes 528ms 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
Unattributable takes 518ms 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 284ms 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 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
67% 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.