Developer Tools

Common workflows in this category

All developer tools

• JWT Decoder

  Decode a JWT into header and payload JSON. The signature segment is ignored, never verified. Paste a token and copy the claims. Processing stays on this page.

• Text Diff Viewer

  Compare original and updated text one line at a time. Matching lines stay put, and changed lines are marked removed or added. Sample presets fill both boxes.

• JSON Compare Online

  Spot what changed between two JSON documents, down to the property that moved, so an API response or a config edit is quick to review before you ship.

• JSON Formatter

  Pretty-print JSON with 2 or 4 spaces, or minify it to one line. Invalid JSON is reported and the previous result is cleared. Copy the output locally.

• Regex Tester

  Test a JavaScript regular expression and list every match with its index and capture groups. Flags are g, i, m, s, u, and y. Updates as you type.

• Byte Size Calculator

  See how many bytes a string, cookie, or header will occupy in UTF-8 and UTF-16, so a size limit is a number you can check before you paste it.

• Cron Expression Parser

  See the next five times a cron expression will run in the timezone you name, so a weekday morning job is a calendar you can check before you deploy.

• URL and Query String Parser

  Break a link or a bare query string into its pieces and read every parameter already decoded, including a key that shows up more than once in order.

• HTML Beautifier

  Indent minified HTML with 2 spaces, 4 spaces, or a tab. Copy or download the formatted markup. Ordinary tags are reindented in your browser.

• Meta Tag Generator

  Draft a page's head tags in one pass: title, description, canonical URL, Open Graph, and Twitter. Add an image or a handle, then copy the finished snippet.

• Robots.txt Generator

  Write a robots.txt that welcomes crawlers to your public pages, blocks the paths you choose, and points them to your sitemap. Copy the starter file.

• XML Sitemap Generator

  Turn a list of absolute URLs into sitemap XML with optional lastmod, changefreq, and priority. Copy or download the urlset. Nothing is uploaded.

• XML Formatter

  Pretty-print XML with a two-space indent so feeds and config files are easy to read, then minify or check the same document. Copy or download the result.

• Redirect & Rewrite Rule Generator

  Generate 301/302 redirects and rewrite rules for Apache .htaccess (mod_rewrite), Nginx and more. Supports regex patterns and bulk lists. Copy-ready output.

• cURL to Python Requests

  Turn a copied cURL command into a Python requests call you can paste into a script, with headers and body kept and common secrets masked before you share it.

• cURL to JavaScript Fetch

  Turn a copied cURL command into a fetch call for the browser or for Node, with the method, headers, and body written out so the snippet is ready to paste.

• SQL Formatter

  Reflow SQL by uppercasing known keywords and breaking before major clauses, or minify it to one line. Comments survive format mode. Copy or download.

• CSS Beautifier

  Turn cramped CSS into a readable stylesheet with two-space or four-space indentation, or compress it to a single line. Copy or download the cleaned result.

• IPv4 CIDR Calculator

  Enter an IPv4 address and prefix to see network, broadcast, netmask, wildcard, and host range. Prefixes /31 and /32 keep every address. Copy the summary.