CSV to JSON Converter
Convert CSV files and spreadsheet data to JSON online instantly. Auto-detects delimiters, supports headers, and outputs as array of objects, arrays, or keyed by column.
About the CSV to JSON Converter
The DevToolHeaven CSV to JSON Converter parses CSV files and transforms them into clean, well-structured JSON using a robust parser that handles quoted values, embedded commas, escaped double quotes, and inconsistent row lengths according to the RFC 4180 CSV specification.
Paste your CSV directly or upload a .csv or .tsv file. The auto-detect feature analyzes the first line to identify whether the delimiter is a comma, semicolon, tab, or pipe character. You can override the detected delimiter manually if needed.
Choose from three JSON output formats to match your use case. Array of Objects is the most common format for APIs and data processing — each row becomes an object with header keys. Array of Arrays omits key names for compact storage or matrix-style processing. Keyed by First Column creates a dictionary keyed by the first column value, ideal for lookup tables.
Smart type coercion converts numeric strings like "42" and "3.14" to JavaScript number type, and boolean strings like "true" and "false" to boolean type. This produces more useful JSON for downstream data processing. Disable these options if you need all values preserved as strings.
Common use cases include: converting spreadsheet data for JavaScript applications, loading exported database records into a JSON-native system, processing form or survey exports, migrating legacy CSV data to REST APIs, and preparing data for JSON-based analytics tools.
All processing is 100% client-side — your data never leaves your browser. Files are read locally using the FileReader API and never uploaded to any server, making this tool safe for confidential business data.
Frequently Asked Questions
The converter supports standard CSV with comma delimiter, semicolon-delimited files common in European Excel exports, tab-separated values (TSV), and pipe-delimited files. Use Auto-detect to automatically identify the delimiter, or select it manually.
Array of Objects (default) creates a JSON array where each row becomes an object with header keys — the most common format for APIs. Array of Arrays creates nested arrays without key names, useful for compact storage. Keyed by First Column creates an object keyed by the first column value, useful for lookup tables.
When enabled, values that look like numbers are converted to JSON number type instead of strings. So "28" becomes 28 in the output. This makes the JSON more useful for calculations and data processing. Disable it if you need all values as strings.
When enabled, values that are exactly "true" or "false" (case-insensitive) are converted to JSON boolean type. So "true" becomes true and "false" becomes false. This is especially useful for CSV exports from databases that store boolean values as text.
The CSV parser follows RFC 4180 and correctly handles values enclosed in double quotes, including values that contain commas, newlines, or escaped quotes (two consecutive double quotes). Multi-line values within quotes are preserved correctly.
Yes. Click the Upload CSV button to select a .csv or .tsv file from your device. The file is read locally in your browser and never uploaded to any server. After loading, click Convert to process the file.
If rows have fewer columns than the header, the missing fields are set to empty strings. If rows have more columns than the header, the extra values are ignored. The converter uses the first row as the definitive header to determine key names for all subsequent rows.
Yes — use the JSON to CSV converter for the reverse operation. It extracts all unique keys from your JSON array as column headers and converts each object to a CSV row, with missing values left as empty cells.
In Excel, save or export the sheet as CSV (File > Save As > CSV). Then paste the CSV content here or upload the file to convert it to JSON. Google Sheets also lets you download as CSV via File > Download > Comma-separated values. The resulting JSON array can be used directly in JavaScript, APIs, or data processing scripts.
For simple CSVs, split by newline and then by comma. For production use with quoted fields and special characters, use the PapaParse library: Papa.parse(csvString, { header: true }) returns an array of objects. Alternatively, paste your CSV here for an instant no-code conversion that handles all edge cases correctly.
Values containing commas must be wrapped in double quotes in the CSV file — for example "New York, NY". This tool's parser follows the RFC 4180 standard and correctly handles quoted values, including values that span multiple lines. If your CSV is not RFC 4180 compliant, values with unquoted commas may be split incorrectly.
Yes — this is one of the most common use cases. Export your database table as CSV, paste or upload it here, and choose the Array of Objects output format. Each row becomes a JSON object with the column headers as keys. The output is ready to use as mock API data, seed data for a development database, or input for a data import script.