CSV ↔ JSON Converter
Convert CSV to JSON and back, live in your browser, with correct quote and delimiter handling.
🔒 Conversion runs only in your browser; your data is never sent to a server.
How it works
Choose a direction — CSV to JSON or JSON to CSV — then paste your data on the left, and the converted result appears on the right instantly, updating with every keystroke. A delimiter selector switches between comma, semicolon (common in European CSV), and tab for TSV files. In CSV to JSON mode, the 'First row is header' toggle sets the shape: on, you get an array of objects keyed by the header names; off, you get a plain array of arrays. Going the other way, paste an array of objects (or even a single object) and it builds the header from the union of every key it finds, so records with different fields still line up in columns. Copy the output or save it as converted.json or converted.csv in UTF-8, and switching direction feeds the current result back in as input for quick round-trips.
When to use it
Reach for it whenever data is in the wrong shape for the next step. Export a sheet from Excel, Google Sheets, or Numbers as CSV and turn it into JSON to seed a database, mock an API, or drop straight into code. Go the opposite way to take a JSON array from an API response or a log file and produce a CSV you can open in a spreadsheet or hand to a non-technical colleague. It also saves you from writing a throwaway parser or spinning up pandas for a one-off reshape, lets you sanity-check that a messy CSV parses the way you expect before importing it somewhere strict, and quickly re-delimits a file between comma, semicolon, and tab.
Accuracy and privacy
Parsing follows RFC 4180, so commas, line breaks, and double quotes inside a quoted field are read correctly: a quoted value such as an address stays a single field, and a doubled quote collapses back to one. On output, any value containing the delimiter, a quote, or a newline is automatically re-quoted so the CSV stays valid, and nested objects or arrays are serialized as JSON text within the cell. Invalid JSON or malformed input surfaces an inline error instead of a silently broken result. Every conversion runs entirely in your browser — nothing is uploaded — so you can process internal spreadsheets or customer records without the data ever leaving your device.
Frequently asked questions
Does it handle commas, quotes, and line breaks inside a field?
Yes. Following RFC 4180, any field wrapped in double quotes keeps its commas, newlines, and escaped quotes intact, so a value like an address or a full sentence never splits across columns.
What if my JSON objects don't all have the same fields?
The CSV header is built from the union of every key found across the array, so mismatched records still line up. Missing values become empty cells, and nested objects or arrays are written as JSON text in the cell.
Is my data uploaded anywhere?
No. Both directions run entirely in your browser, so nothing you paste is sent to a server — safe for internal or sensitive data.