Free Converter
CSV to JSON Converter
Convert CSV data or files to JSON format instantly in your browser. Supports custom delimiters, header detection, and pretty formatting.
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Convert CSV data or files to JSON format instantly in your browser. Supports custom delimiters, header detection, and pretty formatting.
or drag and drop here
CSV (comma-separated values) and JSON (JavaScript Object Notation) are both ubiquitous data interchange formats, but they describe data differently. CSV is flat and tabular: a header row defines field names, and each subsequent row holds one record's values. JSON is hierarchical: data is structured as objects (key-value pairs) and arrays, supporting nesting and richer types. Converting CSV to JSON typically means turning each CSV row into a JSON object whose keys come from the header row and whose values are the row's cells.
This converter parses CSV using PapaParse, the most reliable CSV library in the JavaScript ecosystem. PapaParse handles the quirks that make CSV deceptively hard: quoted fields containing commas, escaped quotes inside quoted fields, mixed line endings, optional BOM markers, and fields containing newlines. The output is structured JSON, formatted with two-space indentation by default for readability.
Two output formats are supported. Array-of-objects (the default) produces [{header1: value1, header2: value2}, ...], the most common JSON shape for tabular data. Array-of-arrays produces [[header1, header2], [value1, value2], ...], preserving column order without using header names as keys.
Most modern APIs and applications speak JSON. Loading data from a CSV export — a sales report, a contact list, a database extract — into a JavaScript application, REST API, or NoSQL database typically requires going through JSON first. The conversion is also the first step for many data transformations, since JSON is easier to manipulate programmatically than CSV.
JSON's structure also unlocks features CSV cannot represent. Objects with nested properties, arrays of varying length per record, and explicit type information (strings versus numbers versus booleans) all become available once the data is in JSON. CSV alternatives like TSV exist but share the same flatness limitation.
Paste or upload your CSV, get JSON.
PapaParse implements RFC 4180 (the CSV spec) plus extensions for the variations real-world CSV files contain. Quoted fields can include commas, newlines, and quote characters (escaped by doubling). Headers, when present, are detected from the first row. Numeric and boolean values can be auto-typed (turned into actual numbers or booleans rather than strings) or kept as strings.
Output JSON is generated using JSON.stringify with optional indentation. Strings are escaped for JSON syntax (backslash, quote, control characters), and structures use the requested format (array of objects or array of arrays).
Edge cases handled: BOM at file start, mixed line endings (\n vs \r\n), empty cells (rendered as empty strings or null depending on settings), trailing newlines, and rows with different field counts. PapaParse's robustness makes it the standard JavaScript CSV library.