Skip to content
https://confex.com

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
94
GRADE
A
FIX
1
REVIEW
3
PASS
11
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
78
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
66
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
92
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
82
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.11 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

4.30 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

54 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.172

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

1.79 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

4.35 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
17
11 PASS 3 REVIEW 1 FIX
D
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Image Optimization
Action
17 images, 0 KB saveable
REVIEW
17 images, 0 KB saveable
Warning::
https://confex.com/images/m-events-logo-2024-white... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://confex.com/images/confex-mevents.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://confex.com/images/SVG/Leaf.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
17 images 403 KB
0 oversized -0 KB
17 legacy format
3 missing dimensions CLS 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

B
JS Execution Cost
682ms total JS execution
REVIEW
682ms total JS execution
Warning::
https://confex.com/: 329ms CPU time
Warning::
Unattributable: 267ms CPU time
Info::
https://confex.com/stylesheets/confex.css: 87ms CPU time
Info::
Third-party scripts: 267ms (39% of total)

Main Thread Breakdown

Other 40% Style & Layout 32% Parse HTML & CSS 13% Rendering 8% Script Evaluation 6%
ScriptTotalScriptingParse/CompileParty
https://confex.com/329ms6ms2ms1st
Unattributable267ms5ms0ms3rd
https://confex.com/stylesheets/confex.css87ms0ms0ms1st
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
646 KB transferred, 28 requests
PASS
646 KB transferred, 28 requests
Info::
Page weighs 1.3 MB (646 KB transferred)
Info::
28 HTTP requests
Info::
Estimated 0.13 g CO2 per page load
646 KB / 2.4 MB budget
646 KB transferred
28 requests
0.13 g CO2 per page load
Images 402.8 KiB 62%
CSS 148.3 KiB 23%
Fonts 42.1 KiB 7%
JavaScript 32.1 KiB 5%
Other 15.0 KiB 2%
HTML 5.8 KiB 1%
0 2.4 MB 4.9 MB
Under budget
A+
Third-Party Impact
11% third-party, 0 ms blocking
PASS
11% third-party, 0 ms blocking
Info::
Third-party code accounts for 11% of page weight (72.7 KiB of 646.0 KiB)
Info::
Third-party blocking time is low (0 ms)
89%
First-party Third-party
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
1 fonts (42 KB)
PASS
1 fonts (42 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

42 KB total

Render-blocking

0

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s 4.0 s FCP 1.1 s LCP 4.3 shttps://fonts.gstatic.com/s/raleway/v37/1Ptug8zYS_SKggPNyC0IT4ttDfA.woff21Ptug8zYS_SKggPNyC0IT4t... https://fonts.gstatic.com/s/raleway/v37/1Ptug8zYS_SKggPNyC0IT4ttDfA.woff2 — 42.1 KiB — 45 ms — font-display: swap
1Ptug8zYS_SKggPNyC0IT4t... woff2 swap
Size 42 KB
Load time 45 ms
Start 940 ms
Risk FOUT — 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
JS Bundles
3 scripts, 0 KB unused
PASS
3 scripts, 0 KB unused
Warning::
https://confex.com/js/highlight.js: unminified — 5 KB could be saved
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://code.jquery.com/jquery-3.4.1.slim.min.js24 KB—✓3rd
https://confex.com/js/highlight.js8 KB—✗1st
https://secure.keep0push.com/js/183673.js0 KB—✓3rd
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
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A+
Page Weight Inventory
28 resources · 646 KB · 0 KB savings available
PASS
28 resources · 646 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 646 KB
Info::
7 third-party resources (11% of weight)
28 resources · 646.0 KiB · 7 third-party Within 1MB page-weight target
Image 65% · 417.7 KiB
CSS 23% · 148.3 KiB
Font 7% · 42.1 KiB
JavaScript 5% · 32.1 KiB
Document 1% · 5.8 KiB
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
28 requests over 1623ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s FCP 1.1 s LCP 4.3 shttps://confex.com// https://confex.com/ — 200 — 5.8 KiB — 356 ms — http/1.1https://confex.com/images/m-events-logo-2024-white.png/images/m-events-logo-2024-white.pn... https://confex.com/images/m-events-logo-2024-white.png — 200 — 2.6 KiB — 123 ms — http/1.1https://fonts.googleapis.com/css?family=Raleway:300italic,400italic,500italic,700italic,300,400,500,700fonts.googleapis.com/css?family=Ral... https://fonts.googleapis.com/css?family=Raleway:300italic,400italic,500italic,700italic,300,400,500,700 — 200 — 1.2 KiB — 117 ms — h2https://fonts.googleapis.com/css?family=Open+Sans:400italic,700italic,400,700fonts.googleapis.com/css?family=Ope... https://fonts.googleapis.com/css?family=Open+Sans:400italic,700italic,400,700 — 200 — 2.0 KiB — 119 ms — h2https://confex.com/stylesheets/confex.css/stylesheets/confex.css https://confex.com/stylesheets/confex.css — 200 — 142.2 KiB — 476 ms — http/1.1https://code.jquery.com/jquery-3.4.1.slim.min.jscode.jquery.com/jquery-3.4.1.slim.m... https://code.jquery.com/jquery-3.4.1.slim.min.js — 200 — 24.1 KiB — 46 ms — h2https://confex.com/js/highlight.js/js/highlight.js https://confex.com/js/highlight.js — 200 — 7.7 KiB — 238 ms — http/1.1https://secure.keep0push.com/js/183673.jssecure.keep0push.com/js/183673.js https://secure.keep0push.com/js/183673.js — 200 — 321 B — 213 ms — http/1.1https://confex.com/images/confex-mevents.png/images/confex-mevents.png https://confex.com/images/confex-mevents.png — 200 — 129.1 KiB — 712 ms — http/1.1https://confex.com/images/SVG/Leaf.svg/images/SVG/Leaf.svg https://confex.com/images/SVG/Leaf.svg — 200 — 1.1 KiB — 357 ms — http/1.1https://fonts.googleapis.com/css?family=Raleway:300,300i,400,400i,500,500i,700,700i,900,900i&subset=latin-extfonts.googleapis.com/css?family=Ral... https://fonts.googleapis.com/css?family=Raleway:300,300i,400,400i,500,500i,700,700i,900,900i&subset=latin-ext — 200 — 929 B — 31 ms — h2https://fonts.googleapis.com/css?family=Open+Sans:400,400i,700,700i&display=swap&subset=cyrillic,cyrillic-ext,greek,greek-ext,latin-ext,vietnamesefonts.googleapis.com/css?family=Ope... https://fonts.googleapis.com/css?family=Open+Sans:400,400i,700,700i&display=swap&subset=cyrillic,cyrillic-ext,greek,greek-ext,latin-ext,vietnamese — 200 — 2.0 KiB — 33 ms — h2https://confex.com/images/bkg-loop-right.png/images/bkg-loop-right.png https://confex.com/images/bkg-loop-right.png — 200 — 45.3 KiB — 120 ms — http/1.1https://confex.com/images/SVG/Search.svg/images/SVG/Search.svg https://confex.com/images/SVG/Search.svg — 200 — 1.3 KiB — 120 ms — http/1.1https://confex.com/images/APSRegDesk2.jpg/images/APSRegDesk2.jpg https://confex.com/images/APSRegDesk2.jpg — 200 — 101.9 KiB — 481 ms — http/1.1https://confex.com/images/SVG/Support.svg/images/SVG/Support.svg https://confex.com/images/SVG/Support.svg — 200 — 2.2 KiB — 124 ms — http/1.1https://confex.com/images/SVG/Collect.svg/images/SVG/Collect.svg https://confex.com/images/SVG/Collect.svg — 200 — 1.6 KiB — 240 ms — http/1.1https://fonts.gstatic.com/s/raleway/v37/1Ptug8zYS_SKggPNyC0IT4ttDfA.woff2fonts.gstatic.com/s/raleway/v37/1Pt... https://fonts.gstatic.com/s/raleway/v37/1Ptug8zYS_SKggPNyC0IT4ttDfA.woff2 — 200 — 42.1 KiB — 45 ms — h3https://confex.com/images/SVG/Schedule.svg/images/SVG/Schedule.svg https://confex.com/images/SVG/Schedule.svg — 200 — 2.0 KiB — 121 ms — http/1.1https://confex.com/images/SVG/Output.svg/images/SVG/Output.svg https://confex.com/images/SVG/Output.svg — 200 — 2.0 KiB — 127 ms — http/1.1https://confex.com/images/SVG/Apps.svg/images/SVG/Apps.svg https://confex.com/images/SVG/Apps.svg — 200 — 2.4 KiB — 177 ms — http/1.1https://confex.com/images/CSTEPanel.jpg/images/CSTEPanel.jpg https://confex.com/images/CSTEPanel.jpg — 200 — 102.6 KiB — 410 ms — http/1.1https://confex.com/images/SVG/Registration.svg/images/SVG/Registration.svg https://confex.com/images/SVG/Registration.svg — 200 — 1.6 KiB — 120 ms — http/1.1https://confex.com/images/SVG/CE.svg/images/SVG/CE.svg https://confex.com/images/SVG/CE.svg — 200 — 2.0 KiB — 118 ms — http/1.1https://confex.com/images/SVG/Exhibits.svg/images/SVG/Exhibits.svg https://confex.com/images/SVG/Exhibits.svg — 200 — 1.7 KiB — 122 ms — http/1.1https://confex.com/images/SVG/Events.svg/images/SVG/Events.svg https://confex.com/images/SVG/Events.svg — 200 — 1.7 KiB — 121 ms — http/1.1https://confex.com/images/SVG/Mail.svg/images/SVG/Mail.svg https://confex.com/images/SVG/Mail.svg — 200 — 1.7 KiB — 120 ms — http/1.1https://confex.com/favicon.ico/favicon.ico https://confex.com/favicon.ico — 200 — 15.0 KiB — 124 ms — http/1.1
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
39% of JavaScript execution is third-party
First-party Third-party 267ms · 0KB · $4/mo
Unattributable
Other
Costly
Execution 267ms
Transfer 0 KB
Monthly Cost $4/mo

These scripts may cost more than they're worth

  • Unattributable adds 267ms and costs ~$4/month

Unattributable 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

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback