Tools & Wizards About Us

Report Summary

  • 25

    Performance

    Renders faster than
    44% of other websites

  • 90

    Accessibility

    Visual factors better than
    that of 74% of websites

  • 75

    Best Practices

    More advanced features
    available than in
    35% of websites

  • 93

    SEO

    Google-friendlier than
    83% of websites

cz.o2.com

O2 | Volání, internet, televize a balíčky O2 Spolu

Page Load Speed

10.3 sec in total

First Response

450 ms

Resources Loaded

7.9 sec

Page Rendered

1.9 sec

About Website

Welcome to cz.o2.com homepage info - get ready to check Cz O2 best content for Germany right away, or after learning these important things about cz.o2.com

O2 nabízí výhodné volání, široké pokrytí i rychlost internetu a další telekomunikační služby. Jejich kombinací i nákupem on-line ušetříte, spojte si služby v O2 Spolu. Zařiďte vše v aplikaci Moje O2.

Visit cz.o2.com

Key Findings

We analyzed Cz.o2.com page load time and found that the first response time was 450 ms and then it took 9.8 sec to load all DOM resources and completely render a web page. This is a poor result, as 90% of websites can load faster.

Performance Metrics

cz.o2.com performance score

25

Measured Metrics

name

value

score

weighting

FCP (First Contentful Paint)

Value3.4 s

37/100

10%

LCP (Largest Contentful Paint)

Value10.8 s

0/100

25%

SI (Speed Index)

Value8.8 s

16/100

10%

TBT (Total Blocking Time)

Value1,510 ms

14/100

30%

CLS (Cumulative Layout Shift)

Value0.013

100/100

15%

TTI (Time to Interactive)

Value16.9 s

5/100

10%

Network Requests Diagram

cz.o2.com

450 ms

osobni

735 ms

index.scss

592 ms

-a220821

291 ms

index.js

100 ms

Our browser made a total of 118 requests to load all elements on the main page. We found that 1% of them (1 request) were addressed to the original Cz.o2.com, 84% (99 requests) were made to O2.cz and 5% (6 requests) were made to S.o2.cz. The less responsive or slowest element that took the longest time to load (3.1 sec) relates to the external source O2.cz.

Page Optimization Overview & Recommendations

Page size can be reduced by 659.3 kB (42%)

Content Size

1.6 MB

After Optimization

920.8 kB

  • HTML
  • Images
  • JavaScript
  • CSS

In fact, the total size of Cz.o2.com main page is 1.6 MB. This result falls beyond the top 1M of websites and identifies a large and not optimized web page that may take ages to load. 50% of websites need less resources to load. Images take 791.2 kB which makes up the majority of the site volume.

HTML Optimization

-79%

Potential reduce by 205.2 kB

  • Original 260.0 kB
  • After minification 251.1 kB
  • After compression 54.9 kB

HTML content can be minified and compressed by a website’s server. The most efficient way is to compress content using GZIP which reduces data amount travelling through the network between server and browser. HTML code on this page is well minified. It is highly recommended that content of this web page should be compressed using GZIP, as it can save up to 205.2 kB or 79% of the original size.

Image Optimization

-33%

Potential reduce by 257.2 kB

  • Original 791.2 kB
  • After minification 534.0 kB

Image size optimization can help to speed up a website loading time. The chart above shows the difference between the size before and after optimization. Obviously, Cz O2 needs image optimization as it can save up to 257.2 kB or 33% of the original volume. The most popular and efficient tools for JPEG and PNG image optimization are Jpegoptim and PNG Crush.

JavaScript Optimization

-44%

Potential reduce by 196.3 kB

  • Original 450.1 kB
  • After minification 449.8 kB
  • After compression 253.8 kB

It’s better to minify JavaScript in order to improve website performance. The diagram shows the current total size of all JavaScript files against the prospective JavaScript size after its minification and compression. It is highly recommended that all JavaScript files should be compressed and minified as it can save up to 196.3 kB or 44% of the original size.

CSS Optimization

-1%

Potential reduce by 604 B

  • Original 78.7 kB
  • After minification 78.7 kB
  • After compression 78.1 kB

CSS files minification is very important to reduce a web page rendering time. The faster CSS files can load, the earlier a page can be rendered. Cz.o2.com has all CSS files already compressed.

Requests Breakdown

Number of requests can be reduced by 18 (17%)

Requests Now

106

After Optimization

88

  • AJAX
  • Images
  • JavaScript
  • CSS

The browser has sent 106 CSS, Javascripts, AJAX and image requests in order to completely render the main page of Cz O2. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 19 to 1 for JavaScripts and as a result speed up the page load time.

Network Requests Diagram

Accessibility Review

cz.o2.com accessibility score

90

Accessibility Issues

ARIA

These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.

Impact

Issue

High

[aria-*] attributes do not match their roles

Contrast

These are opportunities to improve the legibility of your content.

Impact

Issue

High

Background and foreground colors do not have a sufficient contrast ratio.

Best Practices

cz.o2.com best practices score

75

Areas of Improvement

Trust and Safety

Impact

Issue

High

Does not use HTTPS

Low

Ensure CSP is effective against XSS attacks

User Experience

Impact

Issue

High

Displays images with incorrect aspect ratio

General

Impact

Issue

Low

Detected JavaScript libraries

High

Browser errors were logged to the console

High

Missing source maps for large first-party JavaScript

SEO Factors

cz.o2.com SEO score

93

Search Engine Optimization Advices

Crawling and Indexing

To appear in search results, crawlers need access to your app.

Impact

Issue

High

Links are not crawlable

Mobile Friendly

Make sure your pages are mobile friendly so users don’t have to pinch or zoom in order to read the content pages. [Learn more](https://developers.google.com/search/mobile-sites/).

Impact

Issue

High

Document uses legible font sizes

Language and Encoding

  • Language Detected

    CS

  • Language Claimed

    CS

  • Encoding

    UTF-8

Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise Cz.o2.com can be misinterpreted by Google and other search engines. Our service has detected that Czech is used on the page, and it matches the claimed language. Our system also found out that Cz.o2.com main page’s claimed encoding is utf-8. Use of this encoding format is the best practice as the main page visitors from all over the world won’t have any issues with symbol transcription.

Social Sharing Optimization

Open Graph data is detected on the main page of Cz O2. This is the best way to make the web page social media friendly. Here is how it looks like on Facebook: