JSON ↔ CSV Converter

JSON (JavaScript Object Notation) and CSV (Comma-Separated Values) are two of the most common data interchange formats. JSON is hierarchical and supports nested objects and arrays, making it ideal for APIs and configuration files. CSV is flat and tabular, making it perfect for spreadsheets, databases, and data analysis tools. Converting between them is a frequent task in data engineering, reporting, and integration work.

Converting JSON to CSV involves "flattening" nested structures into table columns. A nested object like {"address": {"city": "NYC"}} becomes a column named address.city. Arrays can either be joined into a single cell or expanded into separate rows. The reverse operation — CSV to JSON — takes tabular data and structures it into an array of objects, with optional type detection to convert numeric and boolean strings into proper JSON types.

This bidirectional converter handles both JSON→CSV and CSV→JSON transformations. It supports nested objects with configurable flattening depth, custom delimiters (comma, semicolon, tab), array expansion, header control, and automatic type detection. A live table preview shows you exactly how your data will look. All processing happens in your browser — your data never leaves your machine.

1. Choose your direction — Select the "JSON → CSV" tab to convert JSON arrays to CSV, or "CSV → JSON" to go the other way.
2. Paste your data — Enter a JSON array of objects or CSV text into the input field.
3. Configure options — For JSON→CSV: choose delimiter, toggle headers, enable quote-all or array expansion, and set max flattening depth. For CSV→JSON: toggle first-row-as-headers and auto-detect types.
4. Click Convert — The converter processes your data and shows the result with a live table preview (for JSON→CSV) or formatted JSON output.
5. Copy or download — Copy the result to clipboard or download as a .csv or .json file.

• Bidirectional conversion — Convert JSON arrays to CSV and CSV back to JSON arrays in the same tool.
• Nested object flattening — Automatically flattens nested objects into dot-notation columns (e.g., address.city) with configurable max depth.
• Array expansion — Optionally expand array fields into separate rows instead of joining values into a single cell.
• Custom delimiters — Support for comma, semicolon, and tab delimiters. Auto-detects the delimiter when converting CSV to JSON.
• Type detection — Auto-detect numbers, booleans, and null values when converting CSV to JSON, instead of treating everything as strings.
• Table preview — Live tabular preview of your CSV output, limited to the first 50 rows for performance.
• Download files — Download results as .csv or .json files directly from the browser.
• 100% client-side — Your data never leaves your browser. No server, no uploads, no tracking.

• API data to spreadsheet — Convert a JSON API response to CSV for analysis in Excel, Google Sheets, or LibreOffice Calc.
• Database export processing — Transform JSON database exports into CSV for import into other systems or reporting tools.
• Spreadsheet to API payload — Convert CSV data from a spreadsheet into a JSON array for use in API requests or database imports.
• Data pipeline prototyping — Quickly test JSON-to-CSV transformations before implementing them in ETL pipelines.
• Log analysis — Flatten JSON log entries into CSV format for grep-friendly analysis or import into log analysis tools.