Format, convert, and validate your data in seconds.

Format JSON, convert YAML to and from JSON, convert CSV to and from JSON, convert between Markdown and HTML, and turn a PDF into Markdown — 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

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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.JSON to CSVConvert a JSON array or object into CSV in the browser. Nested objects are flattened into dot-notation columns (address.city) so API responses paste cleanly into a spreadsheet.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.PDF → MarkdownConvert the text in a PDF to Markdown. The file is processed inside your browser and never sent anywhere.

Convert JSON, YAML, CSV, Markdown, HTML, and PDF 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 six formats

Move between the major developer formats on one site. CSV to JSON, JSON to YAML, Markdown to HTML — and back the other way. Pull the text out of a PDF and get Markdown. 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.

Latest from the blog

Featured · 2026-08-02

Why PDF Tables Break When You Convert to Markdown (7 PDFs Tested)

Most PDFs do not carry their visible tables as reusable table structure, so converters have to guess. Measured across 7 real PDFs: the two ways extraction fails, why a plausible-looking table can still be wrong, and what to do next.

PDF #PDF #Markdown

The result of converting a PDF to Markdown shown in FormatArc

2026-07-26JSON to CSV — Nested Objects, Arrays and Nulls Measured on 4 ConvertersConvert JSON to CSV in your browser with no upload. We ran the same 15 JSON inputs through FormatArc, json-2-csv, Miller and pandas: see exactly where they disagree on nested objects, arrays, missing keys and nulls.2026-07-20Migrate Articles Between Dev.to, Hashnode, and Medium — What Each Export Gives YouDev.to stores Markdown, Hashnode exports JSON (plus per-article Markdown via .md URLs), Medium hands you HTML. How to get your posts out, rebuild front matter, keep canonical URLs, and convert leftover HTML to Markdown in your browser.2026-07-17Gmail & Outlook Email to Markdown — No UploadConvert Gmail, Outlook, and .eml email to Markdown in your browser, nothing uploaded. Measured: pasting the full source collapses into a 12-column table.

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