Which delimiters work?

Comma, tab, semicolon, and pipe. Auto counts separators outside quotes on the first record and uses the most common one. A tie stays a comma.

What does the header option do?

With a header, the first CSV row becomes object keys and JSON objects become a header row. Without it, CSV becomes arrays of cells and JSON arrays of arrays are written as rows with no header.

Which values are inferred?

true, false, null, and plain numbers, in either case for the words. A leading zero such as a ZIP code stays a string. A number that does not fit in a JavaScript number keeps the digits from the cell. Turn inference off to keep every cell a string.

How are nested objects written to CSV?

Flatten joins keys with dots, so address.city becomes a column. Leave it off and the nested value is a JSON string in one cell.

CSV JSON converter

Convert CSV to JSON and JSON back to CSV, with a delimiter and a header row you choose.

Runs in browser

Use via MCP

CSV

Table

Tablecsv

name,year,local
Ada,1843,true
"Lovelace, Ada",1815,false

Header row

Infer types

JSON

JSONjson

2 {

3 "name": "Ada",

4 "year": 1843,

5 "local": true

6 },

7 {

8 "name": "Lovelace, Ada",

9 "year": 1815,

10 "local": false

11 }

12]

2 rows · 3 columns · comma

2Rows

3Columns

Use from your agent

Streamable HTTP at https://benchline.fabwaseem.com/mcp. No key. The tool name is convert_csv_json.

mcp.jsonjson

2 "mcpServers": {

3 "benchline": {

4 "url": "https://benchline.fabwaseem.com/mcp"

5 }

6 }

tools/calljson

2 "jsonrpc": "2.0",

3 "id": 1,

4 "method": "tools/call",

5 "params": {

6 "name": "convert_csv_json",

7 "arguments": {

8 "text": "example",

9 "direction": "csv-to-json",

10 "delimiter": "auto",

11 "header": true,

12 "inferTypes": true,

13 "flatten": false

14 }

15 }

16}

Related tools

How it works

Free CSV to JSON and JSON to CSV converter. Pick a comma, tab, semicolon, or pipe, or let the first row decide. Keep or drop the header, infer booleans and numbers, and flatten nested JSON into dotted columns. It runs in the browser.

01
Choose a direction
CSV to JSON reads a table. JSON to CSV writes one. The sample in each direction shows the shape that works.
02
Set the delimiter and header
Auto detects the delimiter from the first record. Turn the header off for a grid with no names.
03
Copy the result
Inferred types and flattened columns are applied before the output is shown. An unclosed quote is reported instead of a partial table.