CSV to JSON Convert
Convert CSV or TSV into clean JSON, with the delimiter detected for you.
CSV to JSON is a free online tool that convert CSV or TSV into clean JSON, with the delimiter detected for you. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Convert
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- 3
- Works offline
- Yes, after the first visit
About CSV to JSON
CSV to JSON is one of 18 convert tools on DuckyTools, and like all of them it runs entirely inside this page. Convert CSV or TSV into clean JSON, with the delimiter detected for you.
How to use it
- Paste the text you want to run through csv to json.
- Set delimiter, first row is a header and detect numbers and booleans.
The 3 settings
| Setting | What it does | Default |
|---|---|---|
| Delimiter | Choose from 5: Detect automatically, Comma, Semicolon, Tab, Pipe. | Detect automatically |
| First row is a header | On or off. On by default. | On |
| Detect numbers and booleans | On or off. On by default. | On |
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
| Controls | Delimiter, First row is a header, Detect numbers and booleans |
Questions
How does delimiter detection work?
It counts commas, semicolons, tabs and pipes in the first non-empty line and picks whichever appears most. That handles the common European semicolon export correctly. Set it explicitly if your data contains a lot of one character inside quoted fields.
Are quoted fields with commas handled?
Yes. The parser follows RFC 4180 — quoted fields may contain the delimiter, line breaks and doubled quotes ("") as an escaped quote character.
Why did my long ID numbers change?
Type detection turned them into numbers, and JavaScript loses precision beyond 2^53. Turn off "Detect numbers and booleans" to keep every value as a string — which is what you want for IDs, phone numbers and anything with leading zeros.