CSV to JSON
Transform spreadsheet rows into structured JSON.
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Maximum input: 5 MB. Files are processed locally; large outputs are available as downloads with a shortened preview.
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How to use CSV to JSON
- Add your CSV data. Paste text or select a file from your device.
- Choose your options. Review the settings and select Convert.
- Save your result. Preview, copy, or download the output.
Know your output.
CSV values stay strings to preserve leading zeros and large IDs. Nested JSON objects use dotted column names; arrays stay JSON text. Spreadsheet-safe mode prefixes potentially executable cells.
Conversion happens locally. Refreshing or closing this tab clears the workspace; downloaded files remain on your device.
CSV to JSON: conversion behavior
Convert CSV rows into JSON objects without uploading the file. Values stay strings, preserving leading zeros, long IDs and the text of dates.
Use this for spreadsheet exports going into an API or a workflow where identifiers must not be rounded or reformatted.
- With the header option enabled, the first row supplies property names. Empty and duplicate names are rejected.
- Without a header, output is an array of arrays and the first row remains data.
- Fields are not automatically converted into numbers, dates, booleans or nested objects. Empty fields remain empty strings.
- Rows must have the same number of fields. Correct the separator or quoting if column counts differ.
Identifiers stay strings
Header enabled, comma separator, two-space indentation. Both IDs remain strings and the quoted multiline note stays one value.
id,name,note
00123,Alex,"hello, world"
9007199254740993,Sam,"line 1
line 2"[
{
"id": "00123",
"name": "Alex",
"note": "hello, world"
},
{
"id": "9007199254740993",
"name": "Sam",
"note": "line 1\nline 2"
}
]Questions about CSV to JSON
Will 00123 stay 00123?
Yes. It becomes the JSON string "00123". Digits already removed by a spreadsheet cannot be recovered.
Why are numeric values in quotes?
All CSV values remain strings. This avoids guessing whether a field is an identifier, decimal or date. Convert selected fields downstream if appropriate.
Understand the next step
Preserve leading zeros when converting CSV to JSONHandle commas, quotes and line breaks in CSVContent reviewed · Conversion behavior & testing