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
58 images, 0 KB saveable
REVIEW
58 images, 0 KB saveable
Warning::
!
https://www.mcmaster.ca/wp-content/themes/child-mc... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.mcmaster.ca/wp-content/themes/child-mc... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.mcmaster.ca/wp-content/themes/child-mc... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.mcmaster.ca/wp-content/themes/child-mc... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.mcmaster.ca/wp-content/themes/child-mc... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.mcmaster.ca/wp-content/themes/child-mc... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
58images2.3 MB
0oversized-0 KB
55legacy format
6missing 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
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
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
12 fonts (182 KB)
PASS
12 fonts (182 KB)
Info::
i
12 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
12
182 KB total
Render-blocking
0
of 12
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
octet-stream;base64,d09...unknownswap
Size5 KB
Load time12 ms
Start2.8 s
RiskFOUT — text flashes from fallback to web font
readmore-arrow.woffwoffswap
Size3 KB
Load time238 ms
Start2.8 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
pxiByp8kv8JHgFVrLDz8Z1x...woff2swap
Size8 KB
Load time99 ms
Start3.1 s
RiskFOUT — text flashes from fallback to web font
pxiEyp8kv8JHgFVrJJfecnF...woff2swap
Size8 KB
Load time91 ms
Start3.1 s
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLGT9Z1x...woff2swap
Size8 KB
Load time68 ms
Start3.1 s
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLEj6Z1x...woff2swap
Size8 KB
Load time63 ms
Start3.1 s
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLCz7Z1x...woff2swap
Size8 KB
Load time56 ms
Start3.1 s
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLBT5Z1x...woff2swap
Size7 KB
Load time69 ms
Start3.1 s
RiskFOUT — text flashes from fallback to web font
ieVl2ZhZI2eCN5jzbjEETS9...woff2swap
Size45 KB
Load time111 ms
Start3.1 s
RiskFOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a...woff2swap
Size37 KB
Load time109 ms
Start3.1 s
RiskFOUT — text flashes from fallback to web font
memvYaGs126MiZpBA-UvWbX...woff2swap
Size42 KB
Load time117 ms
Start3.1 s
RiskFOUT — text flashes from fallback to web font
fontello.woff2woff2swap
Size4 KB
Load time211 ms
Start3.1 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 ~2 KB and ~4 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
3 hints, 0 missing preconnects
PASS
3 hints, 0 missing preconnects
Info::
✓
Page uses 3 resource hint(s)
Current Resource Hints
preconnect—
preload
1
dns-prefetch
2
prefetch—
3 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
Network Waterfall
133 requests over 5586ms
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-party3332ms · 1255KB · CA$46/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
Unattributable
Unattributable
Other
1020ms
0 KB
—
CA$14/mo
Costly
www.mcmaster.ca
www.mcmaster.ca
Other
584ms
13 KB
—
CA$8/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
281ms
128 KB
28%
CA$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
235ms
161 KB
39%
CA$3/mo
Costly
cdnjs
cdnjs.cloudflare.com
CDN
227ms
30 KB
—
CA$3/mo
Costly
Hotjar
script.hotjar.com
Session Replay
218ms
57 KB
67%
CA$3/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
203ms
124 KB
51%
CA$3/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
139ms
97 KB
31%
CA$2/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
136ms
133 KB
51%
CA$2/mo
Optional
www.mcmaster.ca
www.mcmaster.ca
Other
120ms
162 KB
70%
CA$2/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
112ms
125 KB
51%
CA$2/mo
Optional
www.mcmaster.ca
www.mcmaster.ca
Other
56ms
227 KB
89%
CA$1/mo
Optional
Unattributable
Other
Costly
Execution1020ms
Transfer0 KB
Monthly CostCA$14/mo
www.mcmaster.ca
Other
Costly
Execution584ms
Transfer13 KB
Monthly CostCA$8/mo
Facebook Pixel
Advertising
Costly
Execution281ms
Transfer128 KB
Unused28%
Monthly CostCA$4/mo
Google Tag Manager
Tag Manager
Costly
Execution235ms
Transfer161 KB
Unused39%
Monthly CostCA$3/mo
cdnjs
CDN
Costly
Execution227ms
Transfer30 KB
Monthly CostCA$3/mo
Hotjar
Session Replay
Costly
Execution218ms
Transfer57 KB
Unused67%
Monthly CostCA$3/mo
Google Tag Manager
Tag Manager
Costly
Execution203ms
Transfer124 KB
Unused51%
Monthly CostCA$3/mo
Facebook Pixel
Advertising
Optional
Execution139ms
Transfer97 KB
Unused31%
Monthly CostCA$2/mo
Google Tag Manager
Tag Manager
Optional
Execution136ms
Transfer133 KB
Unused51%
Monthly CostCA$2/mo
www.mcmaster.ca
Other
Optional
Execution120ms
Transfer162 KB
Unused70%
Monthly CostCA$2/mo
Google Tag Manager
Tag Manager
Optional
Execution112ms
Transfer125 KB
Unused51%
Monthly CostCA$2/mo
www.mcmaster.ca
Other
Optional
Execution56ms
Transfer227 KB
Unused89%
Monthly CostCA$1/mo
These scripts may cost more than they're worth
Unattributable adds 1020ms and costs ~CA$14/month
www.mcmaster.ca adds 584ms and costs ~CA$8/month
Facebook Pixel adds 281ms and costs ~CA$4/month
Google Tag Manager adds 235ms and costs ~CA$3/month
cdnjs adds 227ms and costs ~CA$3/month
Hotjar adds 218ms and costs ~CA$3/month
Google Tag Manager adds 203ms and costs ~CA$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
Unattributable takes 1020ms 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.mcmaster.ca takes 584ms 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 281ms 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 235ms 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
cdnjs takes 227ms 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
Hotjar takes 218ms 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
67% of Hotjar'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
Google Tag Manager takes 203ms 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 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
51% 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
70% of www.mcmaster.ca'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
51% 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
89% of www.mcmaster.ca'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.