CSV to JSON Converter

How to use

1. Choose the direction: CSV to JSON (default) or JSON to CSV.
2. Paste your input - the delimiter is auto-detected for CSV.
3. Click Convert, then copy or download the result.

Use cases

1. Use case: Migrate spreadsheet data Paste an exported CSV from Google Sheets or Excel and convert it to JSON for seeding a database or API.

2. Use case: Build test fixtures Turn a small CSV table into a JSON array of objects to use as mock data in unit tests.

Practical tips

The first row is treated as the header and becomes object keys — clean headers (no spaces, no duplicates) produce clean JSON. Quoted fields containing commas are handled correctly, but mixed line endings in hand-edited files are the usual parse failure. Output is an array of objects, one per row; nested structures are beyond CSV's shape, so flatten before converting. Verify number columns: values that should stay strings (ZIP codes, phone numbers) can silently become numbers. Like every tool on this site, the Csv To Json runs entirely in your browser: the data you enter never leaves your device, nothing is uploaded to a server, and the tool keeps working if your connection drops.

Common mistakes

CSV has no types, and every classic bug follows from that:

• Leaving spaces or duplicates in header names, which become awkward or colliding object keys in the JSON.
• Hand-editing the CSV and mixing line endings — the usual cause of parse failures in files that look fine.
• Letting ZIP codes, phone numbers and IDs silently become JSON numbers, dropping leading zeros along the way.
• Expecting nested structures: CSV is flat by design, so flatten your data before converting.

Frequently asked questions