CSV to JSON Online — Parse Spreadsheet Data (csv2json)
Paste CSV content or upload a .csv file and the converter sniffs the delimiter (comma, tab, semicolon), reads the header row if present, and emits a JSON array of objects where each column becomes a key and each row becomes an element. Quoted fields, escaped quotes, and values containing the delimiter are parsed according to RFC 4180.
Use this to turn a spreadsheet export into a JSON fixture, load CSV data into a JavaScript REPL, ingest a customer-provided .csv into an API that expects JSON, seed a database from a legacy extract, or normalise data from a SaaS tool that only exports CSV. It is also handy for quick exploration — inspect the JSON in the viewer once converted.
Type inference is opt-in and conservative: "123" is converted to a number, "true" and "false" to booleans, and empty cells become null so downstream consumers can distinguish empty from missing. Cells containing raw JSON like {"id": 1} are parsed into nested objects when possible. Headerless CSV is detected and columns are named col1, col2, etc. Malformed rows surface a clear error pointing to the offending line.
The file is parsed entirely in-browser — no upload to a remote server, which matters when the CSV contains customer data or PII.
About CSV to JSON conversion
Transform CSV and spreadsheet data into structured JSON. Automatically detects delimiters (comma, tab, semicolon), infers data types, and handles edge cases like embedded JSON in cells.
- Auto-detects comma, tab, and semicolon delimiters
- Numbers and booleans converted to proper JSON types
- Headerless CSV detected and handled
- Embedded JSON in cells parsed automatically
- Upload .csv files directly
100% client-side. Your inputs never leave your browser. Ads via AdSense (consent required).
Frequently asked questions
How do I convert CSV to JSON?
Paste CSV data (or upload a file) and the converter detects the delimiter, parses headers, and outputs a JSON array of objects — one object per row with header names as keys. It handles quoted fields, escaped quotes, line breaks inside cells and variable delimiters (comma, semicolon, tab). You can choose an alternative output shape too, such as an array of arrays if you prefer header-less rows.
Is the CSV to JSON converter free?
Yes, fully free, no signup, no file size limit beyond what your browser can hold. JSONCraft has a single open tier across all tools — converters, formatter, diff, viewer. You can push spreadsheets exported from Excel, Google Sheets, or database dumps through it as often as you need.
Does the converter upload my CSV data?
No. The CSV parser runs in your browser — even when you use the file upload button, the file is read with the FileReader API locally, never transmitted. This matters when the CSV contains customer records, email lists or financial data; converting via a server-side tool would send that data outside your control.
How does it handle edge cases like quoted commas or mixed types?
Quoted fields are parsed per RFC 4180, so a comma inside 'Smith, John' doesn't break the row. Fields are output as strings by default, with an option to auto-detect numbers and booleans (true/false, 1/0). For real-world CSVs from Excel and Google Sheets, detection works well, but you can disable it if you have columns like ZIP codes that must stay as strings.
When should I convert CSV to JSON instead of importing directly?
Convert to JSON when the downstream is an API, a document database (MongoDB, CouchDB) or a JavaScript frontend — they all consume JSON natively. Stay in CSV when the downstream is a spreadsheet or a SQL bulk loader. If your CSV has nested-intent columns (user.name, user.email), this converter can be paired with a post-processor to re-nest them, which the flat JSON output makes straightforward.