100% Private Client-Side Processing

CSV to JSON Converter

Convert tabular spreadsheet exports into valid JSON. Automatically parses headers, auto-detects delimiters (comma, semicolon, tab), and handles quoted strings with commas.

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What is the CSV to JSON Converter?

This tool converts CSV (Comma-Separated Values) and TSV files into formatted JSON arrays or nested objects, running entirely inside your browser.

What Goes In

CSV, TSV, or comma/tab-delimited spreadsheet text and files.

What Comes Out

Clean, beautified JSON ready for copying or saving as a .json file.

RFC 4180 State Machine Parsing and Type Inference

Simple string splitting on commas fails whenever cells contain commas, quotes, or line breaks. The parser utilizes a finite state machine that respects RFC 4180: double quotes enclose fields containing delimiters, and two consecutive double quotes ("") represent an escaped quote. Each field is evaluated for primitive types (e.g. "123" becomes integer 123, "true" becomes boolean true).

RFC 4180 Specification: The standard defining how CSV records and fields must handle escaping, separators, and CRLF line breaks.

Type Coercion: Detects whether a column value represents a numeric float, integer, boolean, or literal string.

How to Use the CSV to JSON Converter

Input CSV Data

Paste your raw CSV text into the input box or upload a .csv file from your computer.

Choose Output Structure

Select array of objects (standard for APIs) or array of arrays (compact).

Copy or Download JSON

Inspect the live JSON preview and copy to your clipboard or download the .json file.

Key Settings & Parameters

Setting	What It Controls	Recommended Default
Delimiter	Sets the separator character (Comma for CSV, Tab for TSV, Semicolon for European formats).	Auto-detect or Comma
Parse Numbers & Booleans	Converts "42" to 42 instead of keeping it as a string.	Enabled for database seeding

Common Pitfalls to Avoid

• Unbalanced quotes in CSV cells

If a field contains a quotation mark, ensure it is properly escaped with double quotes ("") according to RFC 4180.
• Mismatched column counts

Ensure every row contains the exact same number of delimiter separators as the header row.

Pro Tips for Best Results

If your Excel spreadsheet exports dates as strings like "2026-03-15", keeping string mode preserves exact ISO format without timezone shifts.

Local Processing Guarantee

Zero server communication. Your customer lists, sales reports, and proprietary spreadsheets are parsed locally.

Engine: In-browser JavaScript CSV tokenizer

When to Use

Importing Excel or Google Sheets exports into MongoDB, Firebase, or PostgreSQL JSONB columns.
Converting tabular analytics data into mock payloads for front-end API testing.
Transforming customer rosters or product catalogs into programmatic fixtures.

When NOT to Use:

Operational Boundaries & Limits:

• Very large CSV files (>50MB or >500,000 rows) can consume considerable browser RAM when converted to verbose JSON objects.

Frequently Asked Questions

In compliance with RFC 4180, fields containing commas are wrapped in quotation marks. The parser recognizes this and preserves the comma as part of the text rather than splitting the column.

Yes. Numeric values are converted to JSON numbers and "true"/"false" are converted to native booleans, unless you disable type parsing.

Yes. Simply select Tab as the delimiter or paste your TSV data directly.

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