convert JSON to CSV with real column control

JSON to CSV free, no upload, no row limits: nested keys become columns, you choose which ones make the cut, and the export streams - a 5 GB NDJSON log converts on a laptop.

how to use it

1. Drop .json or .ndjson - keys become columns straight away.
2. Flatten nested objects into dot-notation columns if you need them.
3. Drop, rename, and reorder columns until the shape is right.
4. Export csv. If it is going into Excel, open csv options first - delimiter, line endings, and the UTF-8 BOM that keeps accents intact all live there.

• Accepts JSON arrays, single objects, and NDJSON; nested structures flatten to dotted columns.
• Rename, drop, reorder, dedupe, sort, filter, and scrub PII before the file ever leaves the tab.
• CSV dialect fidelity: proper quoting, embedded newlines and commas survive round trips.
• CSV written on your terms: comma, semicolon, tab, or pipe; LF or CRLF; and an optional UTF-8 BOM, which is what makes Excel show José instead of José.
• Values keep their meaning: 007 stays 007 and 12.50 stays 12.50 - nothing is helpfully reinterpreted as a number on the way through.
• Or skip CSV entirely: emit SQL INSERTs, a .sqlite database, or TypeScript types instead.

every tool in the box

• data workbench - profile, clean, transform, and export CSV, JSON, and SQLite - the full suite
• JSON flattener - nested JSON or NDJSON to flat columns, arrays and objects unrolled
• CSV PII scrubber - find emails, phones, SSNs, and card numbers - mask, hash, or drop them
• JSON to CSV - convert JSON or NDJSON to CSV with full column control (this page)
• CSV to JSON - convert CSV to JSON or NDJSON, streamed at any size
• Excel to CSV - read .xlsx workbooks and export CSV, sheets and all
• CSV to Excel - write a real .xlsx where leading zeros and dates survive
• SQL on CSV - real SQL over your files: joins, GROUP BY, a read-only console
• CSV to SQLite - drop several files, get one .sqlite database with discovered foreign keys
• CSV to SQL - CREATE TABLE and INSERT statements for Postgres, MySQL, SQL Server, SQLite
• JSON to TypeScript - TypeScript interfaces and JSON Schema derived from your real data
• large CSV viewer - open files past Excel's 1,048,576-row limit without loading them into RAM
• regex painter - highlight example matches, get a verified regular expression back
• encoding fixer - detect windows-1252/UTF-16 and repair garbled text (José → José)
• log parser - read log files as events: layouts detected, stack traces kept whole, timestamps normalized, and a volume-over-time strip drawn in SQL across every row
• visualize - chart any table you have open - bar, line, area or point - drag across it to filter, and export svg, png, or the vega-lite spec that drew it
• theme builder - design, test, and export custom color themes with live previews, palette derivation, and contrast diagnostics

Like every unfckr tool, this runs 100% in your browser: no upload, no servers, no signup, no analytics. A Content-Security-Policy header blocks every programmatic network channel, so not even malicious code could phone home - and you can watch it happen: the privacy page runs six live escape attempts and shows the browser refusing each one.

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