Developer tools

Working with data formats

The JSON Formatter pretty-prints and validates JSON and tells you where parsing fails. To change format rather than tidy it, the JSON to CSV Converter goes both ways, and Table to Spreadsheet takes a table copied from a web page, a Markdown file or an ASCII printout and gives you CSV or Excel. JSON to RDF and the TOON Converter are for narrower jobs: linked data formats, and a compact notation some people use to cut token counts in LLM prompts.

When JSON will not parse, the cause is usually something copied from JavaScript: a trailing comma, single quotes, an unquoted key or a comment. The formatter's error message points you at it. The TOON Converter accepts that kind of relaxed JSON, so it can also read input the strict formatter rejects.

Encoding, comparing and writing

Base64 encodes and decodes, and the Hash Generator produces digests for checking that a file or string has not changed. The Diff Checker highlights what changed between two blocks of text or code. Markdown Preview and the HTML Editor both give a live preview; use the first for writing and the second when you are testing markup, styles or a bit of JavaScript. The CSS Gradient Generator and URL Slug Generator each do one small thing.

AI and web publishing

The AI Token Calculator estimates how many tokens a piece of text uses and roughly what it would cost; treat the numbers as estimates, since every model counts a little differently. The AI Chat Extractor saves a shared ChatGPT, Claude or Grok conversation as Markdown, text or JSON. For site owners there is the llms.txt Generator, the Sitemap Validator and the Website Bandwidth Calculator.

The JSON Formatter, AI Chat Extractor and Sitemap Validator send what you give them to the Fix42 server. If you are working with private data, the JSON to CSV converter and the rest of this category run locally.