CSV ↔ JSON

Client

Turn pasted CSV (or TSV) into JSON objects or raw rows, or flatten JSON arrays and objects into a delimiter-separated table—all parsed locally in your tab.

Learn more: tables and JSON

Turn a rectangular table (CSV) into JSON objects or arrays, or flatten JSON arrays of objects into rows—handy for spreadsheets and data pipelines.

Row-and-column vs nested objects

CSV is flat: each row is a record and columns are fields. JSON can nest objects and arrays. Converters usually map each row to one object and column headers to keys; deeply nested JSON may not round-trip through CSV without flattening or extra conventions.

Delimiters and headers

Pick the delimiter your file uses (comma, tab, semicolon). A header row gives stable property names when building JSON from text pasted from Excel or similar tools.

JSON & CSV

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JSON → CSV turns an array of objects into a header row plus data rows; a matrix of arrays is written row-for-row; a single object becomes a header row and one value row. CSV → JSON with “first row is header” builds an array of objects; otherwise it builds an array of string rows.

Delimiter and quoting follow common spreadsheet rules; embedded newlines inside quotes are preserved.

Sample JSON is pre-filled—choose a delimiter, then JSON → CSV. For CSV → JSON, enable “First row is header” when the first line lists column names.

Nearby workflows on Toolcore

  • JSON formatter — to inspect array-of-objects JSON before shipping to an API.
  • JSON → Excel — when stakeholders need a spreadsheet instead of CSV.
  • Excel → JSON — for the reverse path from uploaded workbooks.

Common use cases

  • Turn a spreadsheet export into JSON objects for scripts or fixtures—set delimiter and header row to match the file.
  • Flatten JSON arrays of objects into a table for quick review in a text editor or email.
  • Inspect CSV that uses tabs or semicolons without changing the source file first.
  • Spot-check a one-off export before loading it into a database or ETL job.

Common mistakes to avoid

  • Forgetting quoted fields with newlines or commas

    RFC-style CSV allows commas inside quotes. If the preview looks wrong, open the file in a sheet app and re-export with consistent quoting.

  • Ignoring a UTF-8 BOM on the first cell

    Some exports prefix a byte order mark. If the header name looks odd, strip the BOM in the source or fix the first column name after conversion.

  • Mismatched row widths

    A ragged CSV (extra commas on some lines) produces uneven JSON rows. Fix the export or drop bad lines before relying on the table shape.

FAQ

Are tables uploaded?

No. Parsing and conversion happen locally in your browser.

Will Excel formulas and dates round-trip?

You paste the exported text the tool sees—usually computed values, not formulas. Date cells become whatever string Excel wrote; verify formats in your sheet before trusting downstream code.

Can I convert huge files here?

Very large pastes can slow the tab. For big datasets, prefer sampling a subset or using a dedicated pipeline; this page is for quick inspection and small/medium extracts.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • csv to json converter
  • json to csv online
  • convert csv to json no upload

More tools

Related utilities you can open in another tab—mostly client-side.