optimizely .blog

4.52

Results collected 2024-04-05 from https://optimizely.blog/

Lighthouse Performance

4.15

The website is fast.
Total Blocking Time: 160 ms 4.70
Largest Contentful Paint: 3.5 s 3.15
Cumulative Layout Shift 5.00
First Contentful Paint: 2.4 s 3.45
Speed Index: 4.3 s 3.75
Avoid an excessive DOM size 1.00
Largest Contentful Paint element 1.00
Preconnect to required origins 1.00
Properly size images 1.00
Reduce unused CSS 1.00
Reduce unused JavaScript 1.00
Max Potential First Input Delay: 360 ms 1.20
Serve static assets with an efficient cache policy: 4 resources found 2.50
First Meaningful Paint: 2.4 s 4.35
Time to Interactive: 3.6 s 4.60
All text remains visible during webfont loads 5.00
Avoid chaining critical requests 5.00
Avoid large layout shifts 5.00
Avoid large layout shifts 5.00
Avoid long main-thread tasks 5.00
Avoid multiple page redirects 5.00
Avoid serving legacy JavaScript to modern browsers 5.00
Avoids document.write() 5.00
Avoids enormous network payloads 5.00
Defer offscreen images 5.00
Diagnostics 5.00
Efficiently encode images 5.00
Eliminate render-blocking resources 5.00
Enable text compression 5.00
Final Screenshot 5.00
Has a <meta name="viewport"> tag with width or initial-scale 5.00
Image elements have explicit width and height 5.00
Initial server response time was short 5.00
JavaScript execution time 5.00
Largest Contentful Paint image was not lazily loaded 5.00
Metrics 5.00
Minify CSS 5.00
Minify JavaScript 5.00
Minimize third-party usage 5.00
Minimizes main-thread work 5.00
Network Requests 5.00
Network Round Trip Times 5.00
Preload Largest Contentful Paint image 5.00
Remove duplicate modules in JavaScript bundles 5.00
Resources Summary 5.00
Screenshot Thumbnails 5.00
Script Treemap Data 5.00
Serve images in next-gen formats 5.00
Server Backend Latencies 5.00
Tasks 5.00
Use HTTP/2 5.00
Use video formats for animated content 5.00
Uses passive listeners to improve scrolling performance 5.00
Enable text compression 5.00

Lighthouse SEO

5.00

The website is really good at SEO!
Document avoids plugins 5.00
Document has a <title> element 5.00
Document has a meta description 5.00
Document has a valid hreflang 5.00
Document has a valid rel=canonical 5.00
Document uses legible font sizes 5.00
Has a <meta name="viewport"> tag with width or initial-scale 5.00
Image elements have [alt] attributes 5.00
Links are crawlable 5.00
Links have descriptive text 5.00
Page has successful HTTP status code 5.00
Page isn’t blocked from indexing 5.00
Tap targets are sized appropriately 5.00
robots.txt is valid 5.00

Lighthouse Best Practices

5.00

The website is adhering to good practice according to Google Lighthouse!
Avoids deprecated APIs 5.00
Avoids third-party cookies 5.00
Uses HTTPS 5.00
Allows users to paste into input fields 5.00
Avoids unload event listeners 5.00
Avoids requesting the geolocation permission on page load 5.00
Avoids requesting the notification permission on page load 5.00
Displays images with correct aspect ratio 5.00
No browser errors logged to the console 5.00
No issues in the Issues panel in Chrome Devtools 5.00
Page has the HTML doctype 5.00
Properly defines charset 5.00
Serves images with appropriate resolution 5.00
Detected JavaScript libraries 5.00
Ensure CSP is effective against XSS attacks 5.00
Page has valid source maps 5.00
Uses HTTPS 5.00
No issues in the Issues panel in Chrome Devtools 5.00
Allows users to paste into input fields 5.00
Avoids deprecated APIs 5.00
Page has the HTML doctype 5.00

W3C HTML

5.00

No errors in the HTML code.
Number of grouped error type: 0 5.00
Number of errors: 0 5.00

Standard Files

5.00

robots.txt seems ok. 5.00
Sitemap seems to work. 5.00
RSS subscription found. 5.00
security.txt seems to work. 5.00

Lighthouse A11y

5.00

The website do not have any apparent issues with accessibility!
Buttons have an accessible name 5.00
Image elements have [alt] attributes 5.00
[aria-*] attributes are valid and not misspelled 5.00
[aria-*] attributes have valid values 5.00
[aria-*] attributes match their roles 5.00
[aria-hidden="true"] is not present on the document <body> 5.00
[user-scalable="no"] is not used in the <meta name="viewport"> element and the [maximum-scale] attribute is not less than 5. 5.00
Background and foreground colors have a sufficient contrast ratio 5.00
Document has a <title> element 5.00
Form elements have associated labels 5.00
Links are distinguishable without relying on color. 5.00
Links have a discernible name 5.00
List items (<li>) are contained within <ul>, <ol> or <menu> parent elements 5.00
Lists contain only <li> elements and script supporting elements (<script> and <template>). 5.00
No element has a [tabindex] value greater than 0 5.00
<html> element has a [lang] attribute 5.00
<html> element has a valid value for its [lang] attribute 5.00
[id] attributes on active, focusable elements are unique 5.00
Heading elements appear in a sequentially-descending order 5.00
Skip links are focusable. 5.00
Image elements do not have [alt] attributes that are redundant text. 5.00
Values assigned to role="" are valid ARIA roles. 5.00
Identical links have the same purpose. 5.00

Sitespeed.io

3.91

About average speed. 3.91
Speedindex: 1590 3.91
Loading time: 1.94s
Number of requests: 24

Yellow Lab Tools

4.45

The website has good frontend code. 4.45
Page weight 5.00
Requests 4.80
DOM complexity 4.85
JS complexity 5.00
Bad JS 5.00
jQuery 5.00
CSS complexity 2.50
Bad CSS 2.40
Web fonts 1.25
Server config 5.00
Number of iframes 5.00
Total JS execution time 5.00
DOM access 5.00
Scroll events bound 5.00
document.write calls 5.00
Synchronous Ajax requests 5.00
Rules count 1.25
Total weight 5.00
Image optimization 5.00
Oversized images 5.00
Gzip/Brotli compression 5.00
File minification 5.00
Requests number 5.00
Different domains 5.00
404 not found 5.00
Connections closed 5.00
Identical content 5.00
Below the fold images 3.65
Webfonts number 1.00
Overweighted webfonts 1.00
WOFF 2 5.00
HTTP protocols 5.00
TLS protocols 5.00
Caching disabled 5.00
Caching not specified 5.00
Caching too short 5.00
jQuery version 5.00
TLS protocols 5.00
IDs duplicated 5.00
CSS syntax error 2.50
Gzip/Brotli compression 5.00
404 not found 5.00
TLS protocols 5.00

Pa11y

4.50

The website can be more accessible, but is rather good!
Number of error type: 1 4.80
Number of errors: 8 4.20

Problems:

Elements must have sufficient color contrast (https://dequeuniversity.com/rules/axe/4.2/color-contrast?application=axeAPI)

Integrity & Security

3.88

Ok integrity but should get better.
Result generated: 2024-04-05 08:42:33 Etc/UTC (Cached for 24 hours)
HTTPS by default: is good! 5.00
HTTP Strict Transport Security HSTS: is good! 5.00
Content Security Policy: is pretty bad. 1.00
Reporting CSP Certificate Transparency Network Error Logging: is good! 5.00
Referrer Policy: is good! 5.00
Subresource Integrity SRI: is pretty bad. 1.00
HTTP headers: is good! 5.00
Cookies: is ok, with 2 error(s) and 0 warning(s). 4.00

HTTP & Tech

3.67

HTTP to HTTPS redirect 5.00
TLSv1.3 support 5.00
TLSv1.2 support 5.00
No IPv6 support 1.00
IPv4 support 5.00
No HTTPv3 support 1.00
No QUIC support 1.00

Carbon Calculator

4.65

Webpage generates very little carbon dioxide!
Carbon dioxide per pageview: 0.32 gram(s)
More green than 93 % of the websites tested by webperf.se (Reference updated: 2022-12-16).
More green than 92 % of the websites tested by webperf.se (Reference updated: 2021-12-12).
Network transfer size: 523 kb 4.65