CSV to JSON Converter
Convert CSV to JSON format easily
CSV to JSON Converter
Enter CSV data with or without headers
How to Use
- Paste your CSV data
- Choose if first row contains headers
- Select your CSV delimiter
- Click Convert to generate JSON
- Copy to clipboard or download as file
Privacy: All conversions happen in your browser. Your data never leaves your device.
Your Privacy is Protected
All processing happens entirely in your browser. No data is stored, transmitted, or tracked. Your information remains completely private and secure on your device.
About CSV to JSON Converter
A CSV to JSON converter is an essential data transformation tool for developers, data analysts, and anyone working with structured data. CSV (Comma-Separated Values) and JSON (JavaScript Object Notation) are two of the most common data interchange formats, each with specific use cases. CSV is widely used for spreadsheets, data exports, and simple tabular data, while JSON is the standard format for web APIs, configuration files, and modern application data. Converting CSV to JSON transforms row-and-column spreadsheet data into structured JavaScript objects that can be easily manipulated by code, consumed by web applications, or sent to APIs. Our converter automatically parses CSV files, identifies headers as object keys, and converts each data row into a JSON object with proper typing and structure. The tool handles edge cases like quoted fields, embedded commas, escaped characters, and different delimiter formats. You can customize the conversion to nest objects, format arrays, handle empty values, and generate JSON in various structures (array of objects, keyed objects, or nested hierarchies). Whether you're importing data into a web application, preparing data for an API, converting spreadsheet exports for programming use, or migrating from legacy systems, CSV to JSON conversion is a fundamental operation that this tool makes instant and error-free.
Key Features
Automatic Header Detection
Automatically identifies the first row as column headers and uses them as JSON object keys. The converter intelligently formats header names, removing special characters and converting spaces to camelCase or snake_case for proper JSON property names.
Custom Delimiter Support
Works with any delimiter—commas, semicolons, tabs, pipes, or custom characters. Upload CSV files from different systems or regions that use different delimiters, and the converter will correctly parse them into JSON objects.
Data Type Detection
Intelligently identifies and converts data types. Numbers become JSON numbers (not strings), booleans become true/false, null values are properly handled, and text remains as strings. This ensures your JSON is properly typed for programming use.
Nested Object Generation
Convert flat CSV data into nested JSON objects. Use dot notation in headers (like 'user.name' or 'address.city') to create hierarchical JSON structures, perfect for representing complex relationships that don't fit naturally in flat CSV format.
Array Formatting Options
Choose how to structure your JSON output—array of objects (most common), keyed objects using a specific field as keys, or nested arrays. Different formats suit different use cases, from direct API consumption to database imports.
Empty Value Handling
Configure how to treat empty CSV fields—convert to null, empty strings, or omit from output entirely. This flexibility ensures your JSON matches the expectations of the systems consuming it.
Large File Support
Process CSV files with thousands of rows and dozens of columns. The converter handles large datasets efficiently, converting extensive spreadsheets into JSON without performance issues or browser crashes.
Download or Copy Output
Copy the generated JSON to your clipboard or download it as a .json file. Preview the JSON structure before exporting, and choose between compact or formatted output for readability or file size optimization.
How to Use the CSV to JSON Converter
Upload or Paste CSV
Upload your CSV file using the file selector, or paste CSV data directly into the input textarea. The converter accepts CSV data from any source—spreadsheet exports, database dumps, or API responses.
Configure Delimiter
Configure delimiter settings if your CSV uses something other than commas (like semicolons for European Excel files, or tabs for TSV files). The tool can often auto-detect delimiters.
Set Header Options
Choose whether the first row contains headers. If yes, these headers become JSON object keys. If no, the converter will generate generic keys like 'field1', 'field2', etc.
Select Output Format
Select your desired JSON output format—array of objects (default), object with keys, or custom structure. Array of objects is most common for API data.
Configure Advanced Options
Configure advanced options like data type detection, empty value handling, and whether to create nested objects from dot-notation headers if your use case requires these features.
Convert to JSON
Click 'Convert to JSON' to transform your CSV. The tool processes the data and displays the resulting JSON in the output panel with syntax highlighting.
Review Results
Review the generated JSON to ensure it's structured correctly. Check a few sample objects to verify that data types and nesting match your expectations.
Copy or Download
Copy the JSON to your clipboard or download it as a .json file. The JSON is now ready to use in your application, API, or database.
Frequently Asked Questions
What's the difference between CSV and JSON?
CSV is a flat, tabular format that represents data as rows and columns, like a spreadsheet. Each row is one record, and each column is one field. JSON is a hierarchical format that can represent nested objects and arrays, supporting complex data structures. CSV is simpler and more human-readable in text form, while JSON is more flexible and better suited for programming. Converting CSV to JSON adds structure and typing that makes data easier to work with in code.
Will the converter preserve data types?
Yes, with data type detection enabled, the converter identifies numbers, booleans, and null values, converting them to proper JSON types rather than strings. For example, '42' becomes the number 42, 'true' becomes the boolean true, and empty fields can become null. This is important because JSON distinguishes between '42' (string) and 42 (number), affecting how programming languages handle the data.
Can I convert CSV with special characters or commas in data?
Yes! The converter properly handles quoted fields, which is how CSV stores data containing the delimiter character. For example, 'John Doe,Senior Developer' in a comma-delimited CSV is treated as a single field because it's quoted. The converter also handles escaped quotes and other special characters according to CSV standards.
How do I create nested JSON from flat CSV?
Use dot notation in your CSV headers. For example, headers like 'user.name', 'user.email', 'address.street', 'address.city' will be converted into nested objects: { user: { name: '...', email: '...' }, address: { street: '...', city: '...' } }. Enable the 'nested objects' option in the converter settings to activate this feature.
What JSON structure should I choose?
For most use cases, choose 'array of objects', which creates: [{ key1: value1, key2: value2 }, { key1: value3, key2: value4 }]. This is the standard format for API data and is easily consumed by most programming languages. Use 'keyed objects' when you want to access data by a specific ID field, creating: { id1: { key1: value1 }, id2: { key1: value3 } }.
Can I convert very large CSV files?
Yes, the converter handles large files efficiently. However, browser-based processing has practical limits (typically up to several thousand rows work smoothly). For extremely large files (hundreds of thousands of rows), consider using command-line tools or server-side processing. For typical use cases with dozens to thousands of rows, our online converter works perfectly.
How do I handle CSV files with no headers?
If your CSV doesn't have a header row, disable the 'first row is headers' option. The converter will generate generic keys like 'field1', 'field2', 'field3', etc. Alternatively, you can add a header row to your CSV before converting, which produces more meaningful JSON with descriptive property names.
Is my CSV data stored or uploaded to a server?
No, all conversion happens entirely in your browser using JavaScript. Your CSV data never leaves your computer, is never uploaded to any server, and is not stored anywhere. This ensures complete privacy for sensitive data. Once you close the browser tab, the data is gone.
Use Cases
- API Data Preparation: Convert CSV data exports into JSON format for POST requests to web APIs. Many APIs accept only JSON, so converting spreadsheet data to JSON enables bulk uploads, data migrations, or batch operations. The structured JSON format ensures your data is properly formatted for API consumption.
- Web Application Data Import: Import spreadsheet data into web applications that use JSON for data storage. Convert user lists, product catalogs, configuration data, or content from Excel/Google Sheets into JSON that your JavaScript application can directly consume without server-side processing.
- Database Migration and Seeding: Convert CSV database exports to JSON for importing into NoSQL databases like MongoDB, which natively understand JSON. Also useful for creating seed data for development databases, converting legacy system exports, or migrating between different database systems.
- Configuration File Generation: Generate JSON configuration files from spreadsheets. Manage application settings, feature flags, or environment configurations in Excel where non-technical team members can edit them, then convert to JSON for deployment. This makes configuration management more accessible.
- Data Visualization Preparation: Convert CSV data to JSON for use with JavaScript charting libraries like D3.js, Chart.js, or Highcharts. Most modern visualization libraries expect JSON-formatted data, so converting CSV enables you to visualize spreadsheet data with powerful web-based visualization tools.