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JSON to CSV Converter

Convert a JSON array of objects into CSV format. Preview the table, copy the CSV, or download it as a file.

CSV Output
Table Preview

About JSON to CSV Converter — JSON to CSV Converter Online

The Oneyfy JSON to CSV converter transforms a JSON array of objects into a clean, downloadable CSV file in one click. Each object in the array becomes a row, and the union of all keys across all objects becomes the header row. The resulting file opens directly in Excel, Google Sheets, or any spreadsheet application. No installation, no account, and nothing ever sent to a server.

Developers, data engineers, and analysts use a JSON to CSV converter when they need to move data from an API response or JSON export into a spreadsheet for reporting, sharing with non-technical colleagues, or further analysis. REST APIs almost universally return JSON, but business stakeholders typically need CSV or Excel. This converter bridges that gap instantly — paste the JSON, click convert, and download the file ready for import.

How to Use the JSON to CSV Converter

  1. Paste your JSON array — a structure starting with [ and containing objects — into the input textarea.
  2. Select your preferred Delimiter from the dropdown: Comma for standard CSV, Semicolon for European locale compatibility, Tab for TSV, or Pipe for pipe-delimited formats.
  3. Click Convert to CSV — the converter validates your JSON, builds the header row from all object keys, and outputs the CSV in the text area below.
  4. Review the Table Preview to verify the data looks correct before downloading.
  5. Click Download CSV to save the file, or use Copy CSV to copy the output to your clipboard.

Supported Input Formats

The converter handles a range of JSON structures commonly returned by APIs and database query tools.

  • Flat object arrays: The ideal input — an array where each object has the same set of primitive (string, number, boolean) keys. Converts with perfect 1:1 column mapping.
  • Mixed-key arrays: Objects with different keys are handled correctly. The converter builds a header from the union of all keys, and missing values for a given row appear as empty cells rather than causing errors.
  • Nested objects and arrays: Nested structures do not map naturally to flat CSV rows. Values that are objects or arrays are serialized as JSON strings into a single cell, preserving the data without losing it.

Tips for Getting the Best Results

A few preparation steps help produce cleaner CSV output, especially when working with API data or database exports.

  • Flatten nested objects first: If your JSON has deeply nested fields you need as separate columns, flatten the structure before pasting it in. For example, transform {"address":{"city":"NYC"}} to {"address_city":"NYC"} so city becomes its own column.
  • Use semicolon delimiter for European Excel: Excel in European locales uses semicolons as the default CSV separator. If your colleagues open the CSV and see all data in one column, re-export using the Semicolon delimiter option so it opens correctly without requiring import wizard settings changes.
  • Check the table preview before downloading: The table preview shows the first 200 rows rendered as a visual table. Verify column alignment and that values appear in the right columns before downloading, especially when working with mixed-key arrays.
  • Remove wrapper keys if needed: Many APIs wrap their array in an outer object: {"data":[...]}. Extract just the array portion (the part starting with [) before pasting, as the converter expects a bare JSON array at the top level.
  • Handle null values deliberately: JSON null values appear as empty cells in the CSV output. If your downstream tool treats empty cells differently from zeros or "N/A" strings, replace null values in your JSON before converting.

Why Use a JSON to CSV Converter Online

Browser-based conversion requires no Python scripts, no Excel Power Query setup, and no command-line tools. It works on any operating system and any device with a browser. Since conversion happens entirely in your browser's JavaScript engine, confidential API responses — such as user data, financial records, or internal metrics — are never transmitted to any server, making it safe for sensitive business data.

Developers benefit most when iterating quickly during API integration work. Data analysts can pull JSON from monitoring dashboards or reporting APIs and convert directly to spreadsheet-ready CSV without writing one-off scripts. Product managers and business analysts who receive JSON data files from engineering teams can self-serve the conversion without waiting for technical help.

Frequently Asked Questions about JSON to CSV Converter

The converter builds the CSV header from the union of all keys found across every object in the array. If some objects have a "phone" key and others don't, "phone" still appears as a column header. Rows for objects that lack that key simply have an empty cell in that column. This ensures no data is lost even when the array contains structurally inconsistent records, which is common in real-world API responses.
Values that contain the delimiter character, double quotes, or newlines are automatically wrapped in double quotes per the RFC 4180 CSV standard. Internal double quotes are escaped by doubling them — so a value like She said "hello" becomes "She said ""hello""" in the CSV output. This ensures the file opens correctly in Excel and Google Sheets without manual fixing.
Nested objects and arrays don't map naturally to flat CSV columns. The converter serializes nested values as JSON strings into a single cell rather than silently dropping them. For example, {"tags":["red","blue"]} becomes the cell value ["red","blue"]. For best results, flatten your JSON to a single level before converting so each field becomes a proper column in the output.
No. All conversion happens entirely in your browser using JavaScript. Your JSON data never leaves your device and is never transmitted to any server. This makes it safe to use with confidential API responses, internal business data, or any JSON that should not be processed by a third party.
Yes, completely free. No account, no sign-up, and no usage limits. Convert as many JSON arrays as you like. Since all processing happens in the browser, there are no server costs involved, so the tool remains free with no hidden tiers or file size restrictions.
There is no enforced size limit. The converter is constrained only by your browser's available memory. JSON arrays with tens of thousands of objects convert quickly. For very large files (several hundred MB), performance depends on your device's RAM. If you hit browser memory limits, consider splitting the array into smaller chunks and converting them separately.
Column order follows the key order found in the first object of the array (with additional keys from subsequent objects appended). To control column order, reorder the keys in your JSON objects before pasting — the converter preserves the key insertion order as defined by the JavaScript specification for modern browsers.
Yes. The converter works in mobile browsers on iOS and Android. You can paste JSON from your clipboard, convert it, and use the Copy CSV button to copy the output. The Download CSV button triggers a file download that saves to your device's Downloads folder, though exact behavior depends on your mobile browser's download handling settings.