Format, convert, and validate your data in seconds.

Format JSON, convert YAML to and from JSON, turn CSV into JSON arrays, and convert between Markdown and HTML — all in your browser. No signup, no upload, no data leaves your machine. Pick a tool below and get your result in seconds.

Open JSON Formatter All tools

7 tools0 serversja / en locales

All converters

JSON FormatterFree JSON pretty printer with readable syntax error messages.YAML to JSONConvert YAML into JSON in the browser. Useful for config files, automation definitions, and quick data inspection.JSON to YAMLConvert JSON to YAML with a browser-only workflow. Paste input, run the conversion, and copy the output without extra setup.CSV to JSONConvert CSV text into a JSON array in the browser. The first row is treated as the header for a predictable output structure.CSV to MarkdownConvert CSV into a GitHub Flavored Markdown table directly in the browser. Ideal for READMEs, issues, and docs.Markdown to HTMLConvert Markdown into HTML in the browser. Supports GitHub Flavored Markdown including tables and task lists.HTML to MarkdownConvert HTML into clean Markdown in the browser. Useful for migrating content from CMSes, web pages, or HTML emails.

Built like a tool, not a landing page

/01

Browser-only by design

All parsing runs in WebAssembly inside the page. Your inputs never leave the tab — safe for production data, configs, and anything under NDA.

/02

Errors that explain themselves

Each parse failure prints a line and column with plain-language guidance. Auto-fix patches simple cases; the rest you can correct in place.

/03

Fast, static, no bloat

Static delivery from S3 + CloudFront. No analytics, no third-party scripts, no popups.

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