Overview
CSV and JSON are the two great interchange formats of the data world: CSV is the spreadsheet's native tongue — rows and columns, human-readable, universally exported — while JSON is the API's — nested, typed, machine-friendly. Moving between them by hand is tedious and error-prone, which is why this converter exists: paste CSV, get clean JSON, with the edge cases handled.
It parses quoted fields (including quotes inside quotes and commas inside quotes), honours your chosen delimiter, and maps the first row to object keys — or generates col1, col2 keys when there is no header row.
Why do CSV and JSON both exist?
Because they solve different problems. CSV is flat and dense: perfect for tabular data — exports from Excel, database dumps, sensor logs. Every row has the same shape, which makes it trivial to scan but hopeless for nesting. JSON is hierarchical: objects inside objects, arrays of anything, which maps naturally to how programs hold data in memory.
Conversion is lossy in one direction: JSON's nesting cannot fully survive the trip to flat CSV (arrays get stringified), but CSV → JSON is clean, because every row becomes one object with named keys. That is the direction this tool handles.
Features
- Proper CSV parsing: quoted fields, escaped quotes and embedded commas handled.
- Four delimiters: comma, semicolon, tab and pipe.
- Header-row toggle — use the first row as keys or auto-generate col1, col2…
- Pretty-print toggle for readable or compact JSON.
- Copy or download the result as a .json file.
- Private: your data never leaves the browser.
Benefits
- No broken imports. Real parser, not a naive split-on-comma.
- European CSVs welcome. Semicolon delimiter for locales that comma-decimate.
- API-ready output. Paste the JSON straight into your code or request body.
- Zero setup. No libraries, no installs, no uploads.
Who can use it
Developers wiring spreadsheet exports into APIs, data analysts preparing JSON for tools that demand it, QA engineers building test fixtures, students learning data formats, and anyone who has ever opened a CSV in a text editor and wished it were JSON. If you regularly move data between Excel and code, bookmark this.
How to use
- Paste your CSV into the input box.
- Choose the delimiter your file uses (comma is the default).
- Tick “first row is headers” if your CSV has a header row.
- Watch the JSON build live; toggle pretty-print as you like.
- Copy the JSON or download it as a .json file.
Frequently asked questions
My CSV has commas inside quoted fields — will it break?
No. The parser follows CSV quoting rules: a field wrapped in double quotes may contain commas, newlines and even escaped double quotes (written as two quotes). The sample input demonstrates all three. Only malformed quoting — an unclosed quote — will confuse it, and then it tells you.
What if my file uses semicolons?
Choose “Semicolon” from the delimiter menu. Many European locales export CSV with semicolons because they use commas as decimal separators. Tab and pipe are covered too.
Can it convert JSON back to CSV?
That is the sibling tool, JSON to CSV, on the Data page — flat JSON arrays convert cleanly. Nested objects get stringified, which is the honest limit of the format.
Is there a size limit?
Only your browser's memory. A few hundred thousand rows convert fine; multi-million-row files may stutter, and for those a desktop tool or script is the better choice.
Is my data uploaded?
No. Parsing and serialisation happen entirely in your browser — sensitive exports stay on your machine.
Conclusion
Rows in, objects out. Paste the CSV, pick the delimiter, take the JSON — the most boring data chore, done in seconds.