Werkzeuge für Website-Betreiber

Calculate the WCAG contrast ratio of two colors live and check AA/AAA compliance for normal and large text.

Four corner sliders generate the matching border-radius CSS code with a live preview to copy.

Set the shadow with sliders, preview it live and copy the CSS code.

Pick two colours and an angle, then copy the ready-made linear-gradient CSS code with a live preview.

Convert colors live between HEX, RGB and HSL - all fields stay in sync.

Generate 5 harmonious random colors at the click of a button, with hex codes to copy.

Encode text to Base64 (UTF-8-safe) or decode Base64 back into text - right in your browser, no upload.

Shrinks CSS by stripping comments and unnecessary whitespace.

Turns a CSV table with a header row into a JSON array, right in your browser.

Convert text in one click to UPPERCASE, lowercase, Title Case, camelCase, snake_case or kebab-case.

Turns a 5-field cron expression into a clear, plain-English description.

Resolve a domain into its IPv4 (A) and IPv6 (AAAA) addresses - fast, server-side, no sign-up.

Strips comments and unnecessary whitespace from HTML and shows the savings in percent.

Encode text into HTML entities or decode them back, right in your browser.

Generate SHA-1, SHA-256, SHA-384 or SHA-512 hashes from any text, right in your browser.

Format, minify and validate JSON - right in your browser, no upload.

Turns a JSON array of objects into a CSV table with a header row, right in your browser.

Paste a JWT token and view its header and payload as readable JSON.

Instantly shows your public IP address and your browser identifier (user agent).

Generate secure random passwords right in your browser - nothing is sent.

Breaks a URL or query string into a clear table of all parameters, URL-decoded.

Test regular expressions live: enter a pattern, flags and test text, and matches are highlighted instantly.

Compares two texts line by line and highlights added lines in green and removed lines in red.

Free URL encoder and decoder: encode text with encodeURIComponent or decode it - right in your browser.

Generates random version 4 UUIDs right in your browser, cryptographically secure.

Convert Unix timestamps into a readable date and back again - in both directions.

Roughly detects the browser and operating system from a user-agent string - right in your browser, no upload.

Automatically adds clean indentation to messy XML - right in your browser.

Converts a number between binary, octal, decimal and hexadecimal - right in your browser.

Create Apache 301 redirects for .htaccess from a simple list of old and new paths.

Generate ready-to-use nginx redirects (location or rewrite syntax) from a list of old/new paths - copy & paste into your server config.

Turn your name, job title and contact details into a ready-to-use HTML email signature with live preview.

Paste your text and instantly see how many hashtags it contains and which ones.

Enter the original price and discount in percent - get the final price and amount saved calculated live.

Ideal image dimensions for Facebook, Instagram, LinkedIn, X and YouTube at a glance.

Counts the characters in your tweet live and uses a traffic-light to show whether you stay under 280.

Build correctly encoded UTM tracking links for your marketing campaigns live - including a copy button.

Calculate your body mass index from height and weight, including your category.

Quickly convert data sizes such as bit, byte, KB, MB, GB and TB between one another.

Enter three values and the fourth is calculated proportionally - right in your browser.

Instantly convert a weight value into all common units: mg, g, kg, t, oz and lb.

Enter a value and instantly convert it into all length units: mm, cm, m, km, inches, feet and miles.

Enter cost price and selling price to instantly calculate profit, margin and markup as a percentage.

Calculate the gross amount from net or vice versa - with 19%, 7% or your own VAT rate.

Calculate X percent of Y, the share as a percentage, or the percentage change from A to B.

Instantly calculate your ROI as a percentage and your profit from the investment and the return.

Calculate the number of days, weeks and approximate months between two dates.

Quickly and freely convert Celsius, Fahrenheit and Kelvin between one another.

Calculate the final amount and interest earned from starting capital, interest rate, term and an optional savings rate.

Loads a page, counts every image and shows which ones have no alt attribute.

Turns link text and target URL into a ready-to-use HTML link tag with nofollow and new-tab options.

Create valid BreadcrumbList JSON-LD for your pages - right in the browser, no sign-up.

Loads a page, collects its internal links and checks which ones lead nowhere (status 404 and similar).

Checks whether a page has a rel=canonical, where it points (self or external domain) and whether the target is reachable.

Turn question-and-answer pairs into ready-to-use FAQPage JSON-LD for your website.

Checks whether a website has a favicon and shows the exact image address.

See the HTTP response headers and status code of any URL - redirects, cache, security headers, content type. Server-side, read-only.

Checks whether a domain automatically redirects its http address to https.

Reads all headings (H1-H6) on a page and shows the outline indented by level, including a warning if there is no H1 or several.

Generate hreflang alternate link tags including x-default for multilingual websites - right in the browser.

Counts the most frequent words in your text and shows their density as a percentage.

Generate the right meta robots tag for your page with a click.

Generate ready-to-use meta tags for title, description, canonical, OpenGraph and Twitter Cards - live in the browser, easy to copy.

Finds insecure http:// resources (images, scripts, links) on your HTTPS page that break the padlock icon and bother Google.

Checks whether a page is set to noindex via meta robots or the X-Robots-Tag header and is therefore excluded from Google.

See how your URL looks on Facebook, LinkedIn & WhatsApp - og:title, image, description & domain loaded live from the HTML.

Generate structured product data as JSON-LD for better Google search results.

Live preview of your Google search result with a length indicator for the title and meta description.

Check in seconds when your domain's SSL certificate expires - with a traffic light and warning. Server-side, read-only.

Generate valid JSON-LD live for Organization, LocalBusiness, FAQPage or Product - ready to copy into your page.

Checks whether your page sends important security headers such as HSTS, CSP and X-Frame-Options - with a traffic-light rating.

Measures the HTML size of a URL in KB and tells you whether the page is lean or unusually large.

Check your XML sitemap: valid format, number of URLs and whether sampled URLs are actually reachable. Server-side, read-only.

Turn a list of URLs into a valid sitemap.xml - right in the browser, no upload.

Turn headlines into clean, search-engine-friendly URL slugs - with correct umlaut handling (ä->ae, ß->ss).

Measure your URL's response time in milliseconds in seconds - with a traffic light for fast, ok or slow. Server-side, read-only.

Reads a URL's title and meta description live, shows the length and whether they are too long or too short.

Copy-ready viewport meta tag for mobile-friendly pages - standard plus variants, with an explanation.

Check whether and where a URL redirects - final status code (traffic light) and final destination URL. Server-side, read-only, no login.

Build your robots.txt with User-agent, Disallow, Allow, Sitemap and Crawl-delay live in the browser.

Fetches a domain's robots.txt, shows the content and counts the Disallow rules.

Instantly check how secure your password is - with a strength rating, entropy in bits and tips.

Convert plain text into binary code (zeros and ones) and back again.

Removes duplicate lines from your text and shows how many lines were deleted.

Convert text with one click to UPPERCASE, lowercase, or Sentence case.

Removes multiple spaces, trims lines, and deletes empty lines.

Check English texts for readability with a Flesch score, rating, and reading time.

Generate as many Lorem Ipsum paragraphs of placeholder text as you need and copy them with one click.

Convert text into Morse code and Morse code back into text - both directions, right in your browser.

Convert an Arabic number into a Roman numeral and back - both directions, instantly.

Reverses your text - by characters, words, or lines, as you choose.

Count characters, words, sentences, and paragraphs, and estimate your text's reading time.

Replace every match of a search term in your text with new text, live.

Count characters, words, sentences, and lines live - with a traffic-light gauge for SEO title (<=60) and meta description (<=155).

Sort lines of text alphabetically or numerically and optionally remove duplicates.