CSV ↔ JSON Converter — Free Online Tool
Input CSV
drop .csv / .json here
Output JSON
CSV to JSON Converter transforms comma-separated values files into JSON arrays or objects, and JSON back to CSV. Paste or upload CSV data, configure delimiters (comma, tab, semicolon, pipe), header row handling, and type inference (numbers and booleans auto-detected vs everything as strings), and get clean JSON output immediately.
CSV (Comma-Separated Values) is the universal format for tabular data exchange — spreadsheet exports, database dumps, analytics reports, and data feeds. JSON is the universal format for web APIs and configuration. Converting between them is a daily task for data engineers, frontend developers working with API data, and analysts moving data between systems.
Type inference is the most important option: with inference enabled, a column of "1,2,3" becomes [1,2,3] (numbers) rather than ["1","2","3"] (strings). Boolean inference converts "true"/"false" and "yes"/"no" to JSON true/false. Without inference, every cell is a string — safer for IDs and codes that look like numbers but should remain strings (e.g., ZIP codes like "00123").
Employee CSV with header row
Result: id,name,active / 1,Alice,true / 2,Bob,false → [{"id":1,"name":"Alice","active":true},{"id":2,"name":"Bob","active":false}]
Tab-separated data (TSV)
Result: Change delimiter to tab — parses TSV files from spreadsheet exports correctly
ZIP codes that must stay as strings
Result: Disable type inference — ZIP code "00123" stays as "00123" not 123
What delimiter should I use?
CSV uses comma by default. TSV (tab-separated) is common for spreadsheet exports. Some European locales use semicolons because commas are used as decimal separators. Pipe (|) is used when data contains commas and quotes. This tool auto-detects the most likely delimiter.
How are quoted fields handled?
Standard CSV quotes fields that contain commas, newlines, or double-quote characters. A quoted field may span multiple lines. Double-quote inside a quoted field is escaped as two double-quotes. The tool handles RFC 4180 compliant CSV including multi-line fields.
What if my CSV has inconsistent column counts?
Rows with fewer columns than the header row get null values for missing fields. Rows with more columns than the header get extra fields named column_N. The tool reports inconsistencies so you can fix them in the source data.
Can I convert JSON back to CSV?
Yes — toggle to JSON to CSV mode, paste your JSON array, and the tool extracts all unique keys as CSV headers and maps values to rows. Nested objects are serialized as JSON strings in the cell.
What is the difference between JSON array and JSON object output?
Array output: [{}, {}, {}] — each row is an object in an array. Object output uses a key field as the object key. Array is more common and compatible with all parsers; keyed object is useful when you need fast lookup by key.