Csv to json

Tabulate

CSV → JSON, entirely in your browser

CSV file

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JSON output

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File size

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Columns

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Rows processed

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Est. memory

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Speed

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Rows / sec

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ETA

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Elapsed

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Drop a CSV, TSV, TXT or .gz file

or click to browse · paste CSV text anywhere · supports files into the gigabytes via streaming

Parse settings

Detected automatically, override anything below.

Delimiter Auto-detect Comma ( , ) Semicolon ( ; ) Tab Pipe ( | ) Custom…

Custom delimiter

Encoding UTF-8 UTF-16 LE UTF-16 BE Windows-1252

Line endings Auto-detect Unix (LF) Windows (CRLF) Classic Mac (CR)

First row is header Auto-detect data types Trim whitespace on every field

Output format JSON array NDJSON (JSON Lines) Nested (grouped by first column)

Pretty-print JSON Skip malformed rows automatically

Keyboard shortcuts: Ctrl+O browse · Ctrl+Enter start · Esc cancel · Ctrl+D download JSON.

CSV preview

First rows read from the source, updates as parsing runs.

Column mapping

Rename, remove, reorder and type columns before conversion.

Column nameRename toTypeInclude

Merge two columns

Creates a new derived column.

Column A

Column B

Separator

New column name

Split a column

Splits one column into two new columns.

Source column

Separator

New column 1

New column 2

Filters

Applied to every row before it's written to the output.

Row search

Match mode Contains Starts with Ends with Regular expression

Column (optional) Any column

Case sensitive Skip fully blank rows Remove duplicate rows

Per-column transforms

Applied in order: case → trim → find/replace.

MDCAT quiz JSON mode

Maps recognized quiz columns to a standardized quiz schema instead of a generic row object.

Enable MDCAT quiz schema output

Looks for columns named (case-insensitive) Question, Option A, Option B, Option C, Option D, Correct Answer, Explanation, Subject, Chapter, Topic, Difficulty, Tags. Missing columns are simply omitted from the schema. Tags are split on commas.

{
  "question": "...",
  "options": { "A": "...", "B": "...", "C": "...", "D": "..." },
  "correctAnswer": "...",
  "explanation": "...",
  "subject": "...",
  "chapter": "...",
  "topic": "...",
  "difficulty": "...",
  "tags": ["...", "..."]
}

Validation report

Rows with structural problems detected during parsing.

No issues yet — run a conversion first.

Row #	Issue	Raw content

JSON preview

Shows the first rows of generated output.

Run a conversion to see output here.

Detailed statistics

Computed as the file streams through.

Conversion history

Stored locally in this browser only.

No conversions yet.

Settings

Export or import your mapping and preferences.

Everything runs locally in your browser. No file ever leaves your device.