CSV or Excel tool
CSV to JSON
Turn CSV rows into a JSON document, using the header row as object keys. Choose whether empty cells become empty strings or null values.
Add files
Drop CSV files here, or choose files. Everything stays on this device.
Waiting for files
Accepted input
- CSV or TSV files
Limits
- Up to 20 MB per CSV/Excel file and up to 100000 rows.
- CSV, TSV, XLSX and JSON inputs are supported in this category.
Local processing
- Files are read in your browser and are never uploaded to a server.
- Nothing is stored after you close or reload the page.
How to use CSV to JSON
- Add a CSV or TSV file.
- Choose whether empty cells should become an empty string or null.
- Press CSV to JSON and download the JSON file.
What it does
- Uses the header row as object keys and keeps every row.
- Can emit an array of objects or an array of value arrays.
- Repeated header names get a numeric suffix so no column is lost.
Limits and things to know
- Values are kept as strings; the tool does not guess numbers, dates or booleans from text.
- A very large CSV may be limited by browser memory rather than the row limit.
Example
Preparing seed data for an app
Given a CSV with name,age,city and three rows, choose objects and an empty string for blanks to get [{ "name": "Alice", "age": "30", "city": "NY" }]. Every value is a string so the output is predictable.
Frequently asked questions
Are numbers converted to JSON numbers?
No. CSV is untyped text, so every value is emitted as a string. Convert types in your application where you know the schema.
How are duplicate headers handled?
Repeated header names get a suffix such as _2, so each column keeps its own value instead of overwriting another.
What happens to blank cells?
You choose. They become an empty string by default, or null when you select that option.
Runs entirely in your browser on ap98.com. Files are never uploaded.