CSV to JSON Converter — No Upload, Instant, Free

About CSV to JSON

This tool converts CSV (comma-separated values) into JSON (JavaScript Object Notation). CSV is the lowest common denominator of tabular data: a plain-text grid where each line is a row and commas separate the columns. JSON is the structured format that web APIs, JavaScript, and most modern tooling consume. The conversion treats the first line of your CSV as the header row, using each column name as an object key, and turns every subsequent line into a JSON object that maps those keys to that row's values. The result is a JSON array of objects, pretty-printed with two-space indentation, with one object per data row.

CSV looks trivial but has real edge cases, and this parser handles the important ones following the common RFC 4180 conventions. A value that itself contains a comma can be wrapped in double quotes so the comma is treated as content rather than a column separator, for example "Smith, John". To include a literal double quote inside a quoted value, you write it twice (""), which the parser collapses back to a single quote. Whitespace around each field is trimmed. Blank lines are skipped rather than turned into empty objects. These rules are what let exports from Excel and Google Sheets convert cleanly, since those tools quote fields exactly this way.

There are deliberate limitations worth understanding. The delimiter is the comma only; semicolon- or tab-separated files (common in European locales where the comma is a decimal separator) are not auto-detected and would need to be converted to commas first. Every value is emitted as a JSON string, including numbers and booleans, so 30 becomes "30" rather than the number 30; the tool does not infer types. The output is a flat array of objects: dotted or bracketed header names are kept as literal keys and are not expanded into nested JSON structures. And because parsing is line-by-line, a quoted field that contains an actual line break across two physical lines is not joined back together.

The typical workflow is exporting a spreadsheet or database table as CSV and converting it into JSON to seed test data, feed a frontend, post to an API, or load into a script. Developers also use it to quickly eyeball whether a CSV is well-formed, since a malformed file or one with only a header row produces a clear error instead of output. The tool needs at least a header row plus one data row to produce results. All conversion happens locally in your browser, so customer lists, financial exports, and other sensitive data never leave your device.