CSV to JSON Converter
Convert CSV tables into JSON arrays of objects with nested dotted headers
Accepted upload: .csv · max 5 MB. Uses the first row as headers. Dotted headers (e.g. address.city) become nested objects. JSON-looking cells parse back into arrays or objects.
CSV input
Paste or upload CSV
JSON output
Convert result
About CSV to JSON
Convert tabular CSV into structured JSON locally. The first row is treated as column headers; each following row becomes one JSON object. Headers with dots such as user.name become nested objects when converted.
How to use
- Paste CSV or upload a .csv file (up to 5 MB).
- Click Convert. The tool parses quoted fields per RFC 4180 and builds JSON objects.
- Copy the JSON or download converted.json.
How conversion works
- Empty cells become null in JSON.
- Dotted header names rebuild nested objects (for example address.city → { "address": { "city": "…" } }).
- Cell values that look like JSON arrays or objects are parsed back into structured values.
Common uses
- Import spreadsheet exports into apps, scripts, or APIs that expect JSON.
- Restore nested fields after flattening with JSON to CSV.
- Preview how a CSV file maps to objects before automation.
Tips
- Include a header row plus at least one data row; a header-only file is not a valid table.
- Keep quotes balanced in CSV fields that contain commas or line breaks.
- Use consistent dotted header naming if you need predictable nesting depth.
Limitations
- Files over 5 MB or malformed CSV (including unclosed quotes) are rejected with an error.
- Very wide sheets produce large JSON objects; consider splitting files for huge datasets.
Privacy
Parsing and conversion stay on your device. ToolsArk does not upload your CSV.
Frequently asked questions
Common questions about the CSV to JSON Converter.
How does the CSV to JSON Converter read my file?
The first row is treated as headers. Each following row becomes one JSON object. Empty cells become null. Quoted fields follow RFC 4180, including commas and newlines inside quotes.
How are nested objects rebuilt?
Dotted headers such as address.city become nested objects: { "address": { "city": "…" } }. Cells that look like JSON arrays or objects are parsed back into structured values.
Does my CSV leave my device?
No. Conversion runs entirely in your browser. ToolsArk does not upload your CSV for conversion.
Why did conversion fail?
Usually the CSV is empty, is not a table (needs a header plus at least one data row), contains an unclosed quoted field, or is larger than 5 MB. Fix the reported error and try again.
Can I download or copy the JSON?
Yes. After a successful conversion you can copy the JSON to the clipboard or download a .json file. You can also upload a .csv file as input.
Need to go the other way?
Use the JSON to CSV Converter to flatten JSON objects into CSV. Both tools share the same conversion engine and keep your data on this device.
Tags
Continue with these utilities
People frequently use these utilities together.