CSV to JSON Converter — Free & Browser-Based
Transform CSV files and spreadsheet exports into structured JSON arrays with automatic type inference, nested object support, and a live preview table. Ideal for developers, data analysts, and anyone moving data between systems.
Drag & drop a CSV file here, or browse
Supports .csv and .txt files
How to Convert CSV to JSON Online
- Drag and drop a .csv or .txt file onto the upload zone, or paste CSV text directly into the input area.
- Choose your delimiter: Comma for standard CSV, Tab for TSV exports, Semicolon for European Excel files, or Pipe for log data.
- Enable First row as headers to use column names as JSON keys; uncheck to generate generic column1, column2 keys.
- Enable Type inference to convert numbers, booleans, and empty cells to their native JSON types.
- Enable Nested JSON to convert dot-notation headers like
user.nameinto nested objects. - Review the live preview table showing the first 5 rows, then click Copy JSON or Download .json.
Key Features
- RFC 4180-compliant parser handles quoted fields containing commas and newlines
- Four delimiter options: comma, tab, semicolon, pipe
- Automatic type inference for numbers, booleans, and null values
- Nested JSON via dot notation (e.g.
address.citybecomes a nested object) - Live preview table for the first 5 rows before conversion
- Row, column, and total cell count statistics
- Pretty-print or compact output, with copy and download buttons
- 100% browser-based — your CSV data never leaves your device
CSV to JSON Use Cases
Converting Excel exports to JSON for REST APIs
Export your spreadsheet as CSV, then use this tool to produce a clean JSON array ready to POST to an API. Type inference ensures numbers stay numbers rather than arriving as strings that require server-side parsing.
Preparing data for MongoDB or Firebase
Document databases expect hierarchical JSON, not flat tables. Dot-notation headers like user.name and address.city are automatically expanded into nested objects, saving manual transformation work.
Tab-separated values (TSV) to JSON conversion
Many analytics platforms and database tools export TSV by default. Switch the delimiter to Tab and the parser handles the format correctly, including quoted fields that span multiple columns.
Automating data pipeline testing
QA engineers can quickly convert CSV test fixtures to JSON for seeding test databases or mocking API responses without writing a conversion script.
FAQ's
No. All processing happens entirely in your browser using JavaScript. Your data never leaves your device and is never transmitted to any server. The tool works offline once the page has loaded.
Comma (,), Tab (\t), Semicolon (;), and Pipe (|). European Excel exports typically use semicolons, while database tools often default to tab-separated values (TSV).
Each cell value is tested in order: if it is empty it becomes null; if it is "true" or "false" (case-insensitive) it becomes a boolean; if it parses as a finite number it becomes a number. Everything else stays as a string.
When a column header contains a dot — for example "address.city" — nested JSON mode expands it into a nested object: {"address": {"city": "…"}}. Multiple dot levels are supported, so "user.profile.avatar" creates three levels of nesting.
Files up to several megabytes (tens of thousands of rows) work well on modern devices. For very large files over 100 MB, a command-line tool such as csvtojson for Node.js will be more efficient.
In Google Sheets, go to File → Download → CSV. Upload or paste the resulting file here. The tool handles the default comma delimiter and quoted fields that Google Sheets uses for values containing commas.
Yes. Uncheck "First row as headers" and the tool generates generic keys — column1, column2, column3, and so on — using the column index. Each row still becomes a JSON object.