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 in your browser. 100% client-side, no upload, no signup. Preserves key order, surfaces row-level parse errors. Supports OpenAPI and Kubernetes config formats.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.

Convert JSON, YAML, CSV, Markdown, and HTML without uploading data

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No upload required

Pasted text is processed inside your browser and never sent to our servers for conversion. Format internal data, API responses, and configs without handing them to an external tool.

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Convert across five formats

Move between the major developer formats on one site. CSV to JSON, JSON to YAML, Markdown to HTML — and back the other way. No more juggling single-purpose tools.

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Same conversion on web, Chrome, and CLI

The browser app, Chrome extension, and npm CLI (formatarc) share the same conversion core. Format in a tab, automate with the CLI when you need to. Open source under the MIT License on GitHub.

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Fix JSON trailing comma errors like Unexpected token } and Expecting property name. See before/after examples and locate the comma by line number in a browser-only formatter.

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FormatArc JSON Formatter parsing JSON after a trailing comma was removed

2026-06-06HTML Table to Markdown Converter — Paste HTML, Get GFM (No Upload)Paste an HTML table and convert it to a GitHub-Flavored Markdown table in your browser. Pipes and line breaks are handled safely — no upload required.2026-06-05Excel or Google Sheets to Markdown Table: Paste and Convert (No Upload)Convert Excel or Google Sheets tables to Markdown by pasting them in your browser. Learn how the tab-separated paste works, why commas can shift columns, and how to keep tables clean in GitHub and Notion.2026-06-02How to Convert JSON to a Markdown Table — Arrays, API Responses, Nested DataTurn a JSON array of objects into a Markdown table. Verify the structure, convert through CSV for a reliable result, handle API responses, and flatten nested JSON — all in the browser.

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