CSV ↔ JSON Converter
Bidirectional CSV ↔ JSON with auto delimiter detection and RFC 4180 quoting
How to use
- Pick CSV → JSON or JSON → CSV
- Paste or upload your data
- Select delimiter and output shape
- Copy or download the result
Use cases
- Data migration
- API payload prep
- Excel → JSON
- Backend seeding
About the CSV ↔ JSON Converter
CSV and JSON are the two most common data interchange formats — CSV for spreadsheets and analytics, JSON for APIs and configuration. Moving between them correctly is harder than it looks: quoted fields, embedded newlines, and non-comma delimiters all break naive converters. This tool implements the RFC 4180 spec and handles every edge case.
Features
- Bidirectional CSV ↔ JSON
- Automatic delimiter detection (comma, tab, semicolon, pipe)
- RFC 4180-compliant quoting — escapes quotes, embedded newlines, delimiters
- First row as header OR array-of-arrays output
- File upload + download
- Union-of-keys header row when JSON rows have different keys
How it works
- Pick CSV → JSON or JSON → CSV.
- Paste or upload your data on the left.
- Choose delimiter (auto-detect by default) and output shape.
- Copy or download the result.
Frequently asked questions
Which delimiters are supported?
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Comma, tab, semicolon, and pipe — either manually selected or auto-detected. The detector sniffs the first non-blank line, ignoring content inside quoted fields.
Does it handle embedded newlines and commas?
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Yes. Fields containing newlines, commas, or quote characters are emitted with RFC 4180 double-quoting and parsed back correctly.
What if my JSON rows have different keys?
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The CSV output uses the union of all keys, preserving first-seen order. Missing cells are empty strings.
Can I convert nested JSON?
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Deeply-nested objects are JSON-stringified into the cell. Flat CSV can't represent true nesting — if you need it, keep the JSON.
Is my data uploaded anywhere?
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No. Conversion happens entirely in your browser; uploaded files never leave your machine.