CSV to JSON Converter
Convert CSV or TSV data to structured JSON with automatic delimiter detection, type inference (numbers, booleans, null), RFC 4180 quoted-field handling, and file upload for large datasets.
Why Use CSV to JSON Converter?
Spreadsheets are where analysts keep data; APIs want JSON. Rather than writing a `csv.DictReader` script for every one-off import, a converter lets you paste a Google Sheets export, pick whether the first row is headers, and get clean JSON back. Auto-type inference (turning `"true"` into boolean, `"42"` into number) saves a second cleanup pass. This is especially useful when seeding development databases, bulk-loading data into a form builder, or prepping fixtures for automated tests. And because it runs in-browser, it's safe for CSVs that include customer emails or internal IDs.
How to Use CSV to JSON Converter
- Paste your CSV data into the input area or upload a .csv file using the Upload button.
- The tool automatically detects the delimiter and converts CSV to JSON in real-time.
- Adjust options: toggle first row as headers, enable auto-detect types (numbers, booleans), or choose output format.
- Copy the JSON output to your clipboard or download it as a .json file.
- Use the Swap button to switch to JSON to CSV conversion mode.
Worked Examples
Convert an employee list
name,role,active\nJane,CEO,true\nBob,CTO,true
[{"name":"Jane","role":"CEO","active":true},{"name":"Bob","role":"CTO","active":true}]Type inference turned "true" into boolean — perfect for direct API use.
Tab-separated data from Excel
Paste a TSV copy from Excel (tab-separated)
Auto-detects tab delimiter; output is standard JSON array.
Works seamlessly with Excel's default copy behaviour (tab-separated).
CSV without headers
123,Jane,2024-01-15\n124,Bob,2024-02-01
[{"column_1":123,"column_2":"Jane","column_3":"2024-01-15"},…]Untoggle "first row as headers" to generate auto column names.
About CSV to JSON Converter
CSV to JSON Converter is a free online tool that transforms CSV (Comma Separated Values) data into structured JSON format. It features automatic delimiter detection (comma, semicolon, tab, pipe), intelligent type parsing that converts numeric strings to numbers and boolean strings to true/false, and proper handling of quoted fields with escaped characters. Output as an array of objects (with column headers as keys) or an array of arrays. The tool correctly handles edge cases like newlines within quoted fields, escaped quotes, inconsistent column counts, and empty values. Perfect for importing spreadsheet data into web applications, preparing data for APIs, or converting tabular data for JavaScript processing. All conversion happens in your browser — your CSV data stays private.
Troubleshooting & Common Issues
Numbers appear as strings in the output
Type inference is disabled or your column contains values that aren't purely numeric (e.g., leading zeros like "01234" or phone numbers). Leading zeros are preserved as strings intentionally — converting them to numbers would strip the zeros. Enable "coerce types" for stricter conversion.
A row with an embedded comma broke the parse
Quote the field with double quotes (RFC 4180): `"Smith, John"`. The parser handles quoted fields correctly. If your source CSV has raw unquoted commas inside values, you'll need to re-export with proper quoting from the origin tool.
Dates come out as strings; I want Date objects
JSON has no native date type — every parser represents dates as ISO 8601 strings. Convert them in your consuming code with `new Date(value)`. The converter preserves the original string so you can apply the right format.
File too large to paste
Use the Upload button instead of paste — it streams the file directly. For files above ~20 MB, split the CSV into chunks or run a local script; the browser's memory limit kicks in around that size.
Frequently Asked Questions
How do I convert CSV to JSON?
Paste your CSV data into the input field or upload a .csv file. The tool automatically detects the delimiter and converts each row into a JSON object using the first row as property keys. The result is a JSON array of objects that you can copy or download.
Does the tool auto-detect the CSV delimiter?
Yes. The auto-detect feature analyzes the first line of your CSV to determine whether it uses commas, semicolons, tabs, or pipes as delimiters. You can also disable auto-detection and manually select a delimiter if needed.
What does auto-detect types do?
When enabled, the tool converts string values to their appropriate JSON types: numeric strings like "30" become the number 30, "true"/"false" become booleans, and "null" becomes null. Disable this option if you want all values to remain as strings.
Can I convert CSV without headers?
Yes. Uncheck 'First row as headers' and the tool will generate automatic column names (column_1, column_2, etc.) instead of using the first row as property keys. All rows including the first will be treated as data.
Is my CSV data safe with this tool?
Yes. This CSV to JSON converter runs 100% client-side in your browser using JavaScript. No data is sent to any server. Your CSV data remains on your device throughout the entire conversion process.
How does the tool handle quoted CSV fields?
The parser correctly handles RFC 4180 compliant CSV: fields wrapped in double quotes can contain commas, newlines, and other special characters without breaking the parse. Double quotes within quoted fields are escaped as two consecutive quotes ("").
What output formats are available?
Two output formats: 'Array of objects' creates [{"name":"John","age":30},...] using headers as keys (most common), while 'Array of arrays' creates [["name","age"],["John",30],...] preserving the tabular structure.
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