CalcChef tool collection
Web Tools
Handle routine web, SEO, and link-building tasks with tools that run directly in your browser.
Start with these tools
UTM Builder
Build a campaign URL with utm_source, utm_medium, utm_campaign, utm_id, utm_term and utm_content. Source, medium and campaign are required.
Sitemap Generator
Paste one URL per line to get a sitemap.xml: addresses percent-encoded and XML-escaped, duplicates removed, and a lastmod date where you add one after a |.
Robots.txt Generator
Build a robots.txt from a preset such as Block AI crawlers or WordPress, or block and allow folders for named bots, with Sitemap lines and every path checked.
Meta Tag Generator
Generate HTML meta tags for a page: title, meta description, charset, viewport, robots and canonical, plus optional author, keywords and social tags.
All Web Tools
13 free browser-based tools
JSON to Query String
Turn a JSON object into a URL query string: arrays as repeated keys, [], [0], a comma list or JSON, nested objects as user[name], user.name or JSON.
JWT Decoder
Paste a JSON Web Token to read its header, its payload and the exp, nbf and iat times in UTC. The signature is shown but not checked: nothing is verified.
Mailto Link Generator
Make a mailto: link with To, CC, BCC, subject and body. Body line breaks become %0D%0A as RFC 6068 requires, and the link copies as HTML too.
Meta Tag Generator
Generate HTML meta tags for a page: title, meta description, charset, viewport, robots and canonical, plus optional author, keywords and social tags.
Open Graph Generator
Write Open Graph meta tags for link previews: og:title, og:type, og:url and og:image, plus description, site name and image alt, with a required-tag check.
Query String to JSON
Paste a query string or a full URL to get JSON: repeated keys and key[] become arrays, + and %20 decode to spaces, with optional nesting and number types.
Robots.txt Generator
Build a robots.txt from a preset such as Block AI crawlers or WordPress, or block and allow folders for named bots, with Sitemap lines and every path checked.
Sitemap Generator
Paste one URL per line to get a sitemap.xml: addresses percent-encoded and XML-escaped, duplicates removed, and a lastmod date where you add one after a |.
Slug Generator
Turn a title into a lowercase URL slug joined by hyphens or underscores. Accents go, ß, æ and ø are spelled out, and letters with no Latin form are listed.
Twitter Card Generator
Make twitter:card, site, creator, title, description and image meta tags for a summary or large-image card on X, with checks on @handles and the image URL.
URL Parser
Split a URL into protocol, user name, password, host, port, path, query and hash, see each query parameter decoded, and whether the port was written.
UTM Builder
Build a campaign URL with utm_source, utm_medium, utm_campaign, utm_id, utm_term and utm_content. Source, medium and campaign are required.
WhatsApp Link Generator
Build a wa.me click-to-chat link and its QR code from a phone number in international format and an optional message, percent-encoded after ?text=.