Convert CSV to JSON

CSV to JSON conversion turns each spreadsheet row into a JSON object and uses the first row as property names. The result is a standard JSON array that can be used in APIs, applications, databases, test fixtures, and development workflows.

With FileGizmo, the conversion happens entirely inside your browser. Select a CSV file or paste CSV text, review the delimiter and output options, then download the finished .json file. Your source data is never uploaded, so customer lists, financial exports, research data, and internal records remain on your device.

The converter detects commas, semicolons, tabs, and pipes, including quoted fields containing delimiters. Empty rows are skipped automatically. Smart types are enabled by default to convert recognizable numbers, booleans, and empty cells into useful JSON values. Identifier-like values with leading zeros remain text, and you can switch smart types off when every value must stay a string. A result preview lets you verify the structure before downloading it.

CSV looks simple, but correct parsing requires more than splitting every line at commas. Quoted fields may contain separators, line breaks, or escaped quotation marks. Regional exports often use semicolons because commas represent decimals, while analytics tools may produce tabs or pipes. FileGizmo uses a CSV parser that respects quoted fields and lets you override automatic detection when you know the source format.

The first row becomes object keys, so clear and unique headings produce the most useful JSON. Duplicate or blank headings can create ambiguous data for downstream code. Review them in the source spreadsheet before converting, and consider short machine-friendly names when the JSON will feed an API. Every subsequent non-empty row becomes one object. Missing cells remain empty values according to the selected typing behavior.

Smart types reduce cleanup by recognizing ordinary numbers, true, false, and empty cells. They can also change meaning if used carelessly. Postal codes, account numbers, SKUs, and identifiers such as 007 are not quantities and often need leading zeros. The converter protects identifier-like leading-zero values and offers a switch that keeps every cell as text when exact lexical preservation matters.

After conversion, preview the opening records and compare field names, row count, and representative edge cases. Search for a value containing a comma or line break to confirm the source was parsed as intended. JSON output is an array of objects, a common shape for application fixtures, imports, scripts, and API payload preparation. Validation by the destination application is still important because each system can impose its own required fields and types.

Large datasets consume browser memory as both parsed rows and formatted JSON. A desktop browser is preferable for hundreds of thousands of records. Split extremely large CSV files first when possible. Customer lists, research exports, and internal operational data remain on the device throughout the conversion, eliminating a server copy but not the need to protect the downloaded result.