What JSON format does the converter accept?

The input must be a JSON array of objects (rows). Example: [{"name":"Alice","age":30},{"name":"Bob","age":25}]. Each object becomes a row and the keys become column headers.

Can I convert CSV with semicolons?

Yes. Select "Semicolon (;)" as the delimiter in the options bar before converting. This is common for European locale CSV files.

Does CSV to JSON auto-detect types?

Yes. Numeric strings become numbers, "true"/"false" become booleans, "null" becomes null, and strings that look like JSON are parsed into nested structures.

Yes. Click the "Upload" button to select a .json, .csv, or .txt file. The file contents are loaded into the input area.

TSV (Tab-Separated Values) uses tabs instead of commas. Select "Tab" in the delimiter options to work with TSV files.

Yes. All conversion runs in your browser. Nothing is uploaded, stored, or transmitted anywhere.

JSON ↔ CSV Converter

Convert between JSON and CSV formats instantly — free, browser-based

JSON

CSV

Options

Delimiter

Include header row

Input (JSON)

Upload

Output (CSV)

Free JSON to CSV Converter & CSV to JSON Converter Online

JSON and CSV are the two most common data formats used across software development, data analysis, and business intelligence. JSON (JavaScript Object Notation) is the standard data format for web APIs and modern applications. CSV (Comma-Separated Values) is the universal format for spreadsheets, databases, and data exports. You frequently need to convert between them — and this tool makes that conversion instant, accurate, and free.

The OmniWebKit JSON to CSV Converter works in both directions. Paste a JSON array of objects to convert it to a properly formatted CSV file with configurable delimiters and optional header rows. Paste a CSV file to convert it back to a structured JSON array, with automatic type coercion (numbers, booleans, and null values are detected and converted automatically). All processing happens in your browser — your data never leaves your device.

Four delimiter options are supported: comma (the default), semicolon (common in European locales where commas are used as decimal separators), tab (for TSV files), and pipe. The "Swap" button reverses the conversion direction and moves the output to the input area, so you can quickly convert back and forth.

JSON to CSV Conversion — How It Works

Converting JSON to CSV requires the input to be a JSON array where each element is an object (row). The converter handles several edge cases automatically:

Missing keys

If different objects in the array have different keys, the converter collects all unique keys across all objects. Missing values for a given row appear as empty cells in the CSV output.

Nested objects and arrays

If a JSON value is an object or array, it is serialised to a JSON string and placed in a single CSV cell, surrounded by quotes. This preserves the data without losing it.

Special characters

Values that contain the delimiter character, double quotes, or newlines are automatically wrapped in double quotes per the RFC 4180 CSV standard. Double quotes within values are escaped by doubling them.

Header row

The first row of the CSV output uses the JSON object keys as column headers. You can disable this for header-less CSV output.

Custom delimiters

Choose from comma, semicolon, tab, or pipe. Semicolons are common in German, French, and other European locales where commas are decimal separators. Tab-separated values (TSV) are often easier to paste into Excel.

CSV to JSON Conversion — Smart Type Detection

When converting CSV to JSON, the converter doesn't just produce strings for every value — it applies smart type coercion to produce the most useful JSON output:

Numbers

Numeric strings are automatically converted to JavaScript numbers. "42" becomes 42, "3.14" becomes 3.14.

Booleans

"true" becomes true (boolean), "false" becomes false. Case-sensitive.

Null values

"null" is converted to JSON null instead of the string "null".

Nested JSON

Strings that look like JSON objects or arrays ({...} or [...]) are parsed into nested structures.

Empty cells

Empty CSV cells become empty strings "" in the JSON output.

Column names

If "First row is header" is unchecked, columns are named column_1, column_2, etc.

Frequently Asked Questions

Is this JSON to CSV converter free?+

Yes, completely free with no usage limits, no account required, and no data uploaded to any server. All conversion runs in your browser.

Is my data private?+

Yes. Your data is processed entirely in your browser using JavaScript. Nothing you paste is uploaded, stored, or transmitted anywhere.

What JSON format does the tool accept?+

The JSON input must be an array of objects (rows). Example: [{"name":"Alice","age":30},{"name":"Bob","age":25}]. Nested objects are serialised to JSON strings in the CSV cells.

Can I convert a CSV with semicolons?+

Yes. Select "Semicolon (;)" as the delimiter in the options bar before converting. Semicolons are common in European locales.

What happens to missing fields in JSON to CSV?+

If objects in the JSON array have different keys, all unique keys are collected and used as columns. Objects missing a key produce an empty cell in that column.

Can I upload a file instead of pasting?+

Yes. Click the "Upload" button to select a .json, .csv, or .txt file from your device. The file contents are loaded into the input area.

Why are my numbers appearing as strings in the CSV?+

CSV is a plain-text format — all values are strings. When you convert back from CSV to JSON, the tool automatically detects and converts numeric strings back to numbers.

What is a TSV file?+

A TSV (Tab-Separated Values) file uses tabs instead of commas as the delimiter. Select "Tab" in the delimiter options to work with TSV files.