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 / es / pt 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

/01

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.

/02

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.

/03

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.

Latest from the blog

Featured · 2026-06-18

JSON vs YAML vs CSV vs Markdown: Data Format Comparison Cheatsheet

Compare JSON, YAML, CSV, and Markdown in one page: decision matrix, feature comparison, comment support, parser ecosystem, LLM context guidance, and browser-side conversion between all four formats.

JSON #JSON #YAML

FormatArc CSV to Markdown conversion result, illustrating the cross-format hub between JSON, YAML, CSV, and Markdown

2026-06-16Paste HTML as Markdown: Remove Spans, Inline Styles, and Word CruftConvert messy HTML from Word, Google Docs, ChatGPT, or web copy into clean Markdown. Strip spans, inline styles, classes, and Word-specific markup in your browser — no upload.2026-06-14Markdown Table Not Rendering or Broken? Fix It by SymptomDiagnose a broken Markdown table by symptom: renders as plain text, columns shift, cells split at a pipe. Tested on GitHub, marked, and remark-gfm — fix column counts, blank lines, and pipe escapes in order.2026-06-08JSON Trailing Comma: Why It Fails and How to Remove It (RFC 8259)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.

View all articles