CSV to JSON Converter

What is CSV?

CSV (Comma-Separated Values) is a plain-text format for tabular data. Each line is a row and values within a row are separated by a delimiter, typically a comma, semicolon, or tab. CSV is one of the most common data interchange formats used by spreadsheets, databases, and data pipelines.

Why convert CSV to JSON?

JSON is the native data format for JavaScript and most modern web APIs. Converting CSV to JSON lets you feed data from spreadsheets directly into web applications, REST APIs, or JavaScript code. JSON also supports typed values (numbers, booleans, null) that CSV cannot express natively.

How does type inference work?

When type inference is enabled, the converter automatically promotes cell values to their most appropriate JSON type:

• Numeric strings like "42" or "3.14" become JSON numbers.
• "true" and "false" (any case) become JSON booleans.
• Empty strings and the literal text "null" become JSON null.
• Everything else stays a string.

Handling special characters

Fields that contain the delimiter character, line breaks, or double-quote characters must be wrapped in double quotes. Two consecutive quotes ("") inside a quoted field represent a single literal double-quote. The PapaParse library handles all of these cases automatically.

Flat vs. nested JSON

This tool outputs flat JSON: an array of objects where each object represents one row, and each key is a column header. Example:

[
  { "name": "Alice", "age": 30 },
  { "name": "Bob", "age": 25 }
]

Nested JSON groups data by relationships, e.g., all rows with the same ID under one parent object. CSV is inherently flat; generating nested structures requires a follow-up transformation (e.g., using Array.reduce() in JavaScript or a tool like jq).

JSON Lines (JSONL)

JSONL (also called newline-delimited JSON) is a variant where each line is a separate JSON object with no wrapping array:

{"name":"Alice","age":30}
{"name":"Bob","age":25}

JSONL is common in data pipelines (BigQuery, Elasticsearch bulk API, Apache Spark) because it's streaming-friendly - you can process one record at a time without loading the entire file into memory. To convert CSV to JSONL, generate the array, then write each object on its own line without commas or brackets.