JSON to CSV Converter
Convert JSON arrays and objects to RFC 4180-compliant CSV. Flatten nested keys, choose delimiter, preview the table, and download — entirely client-side.
What is a JSON to CSV Converter?
Overview and core technical concepts
A JSON to CSV Converter transforms structured JSON arrays of objects into Comma-Separated Values (CSV) files ready for opening in Microsoft Excel, Google Sheets, or database imports.
Why Convert JSON to CSV?
Key advantages, developer speedups, and security benefits
Export API Data into Spreadsheets
Transform REST API response payloads into business spreadsheets for financial analysis or reporting.
Import Data into SQL Databases
CSV files are widely supported by PostgreSQL, MySQL, and SQLite import wizards.
When Shouldn't You Use CSV?
Anti-patterns, limitations, and when to choose an alternative approach
CSV is a flat 2D tabular format. Deeply nested objects require flattening or XML/JSON formats.
JSON to CSV Example
Sample inputs, expected outputs, and code patterns
Converting Array of Users
[{"id":101,"name":"Alice"},{"id":102,"name":"Bob"}]id,name
101,Alice
102,BobCommon CSV Conversion Mistakes
Frequent errors, security risks, and how to fix them
Frequently Asked Questions
Absolutely. ToolZeno's JSON to CSV Converter runs 100% client-side inside your web browser. Your JSON data is never sent to any server, stored online, or logged anywhere. All parsing, flattening, and CSV generation happen entirely in your device's memory using JavaScript — fully air-gapped from any backend.
When the "Flatten nested" option is enabled, nested objects are recursively expanded into dot-separated column names. For example, { "address": { "city": "NYC", "zip": "10001" } } produces two columns: address.city and address.zip. You can customise the separator to use underscores, hyphens, or any string you prefer.
Arrays that appear as values inside JSON objects (e.g. "tags": ["react","typescript"]) are serialised as a JSON string in a single cell — e.g. ["react","typescript"]. This preserves all data without losing information. Root-level JSON arrays are treated as separate rows.
ToolZeno supports four standard delimiters: Comma (,) — the default CSV standard; Semicolon (;) — common in European locales where comma is used as decimal separator; Pipe (|) — useful when data contains commas and semicolons; Tab (\t) — produces TSV (Tab-Separated Values) compatible with most spreadsheet applications.
Yes. The converter accepts files up to 10 MB via drag-and-drop or file upload. For very large datasets (200+ rows), the Table Preview activates virtual scrolling — only the visible rows are rendered in the DOM, keeping the browser fast and responsive even with thousands of rows.
Yes. By default, ToolZeno uses CRLF (\r\n) line endings and RFC 4180-compliant quoting — both required by Excel. If your data contains commas inside values, the Minimal quote strategy will automatically wrap those cells in double-quotes. For European Excel installs that expect semicolons, simply switch the delimiter to ";".
Yes. The converter is fully Unicode-aware. Characters like accented letters (é, ü, ñ), CJK characters (中文, 日本語), Arabic, and even emoji (🚀, ✅) are preserved exactly as-is in the CSV output. Special CSV characters (commas, double-quotes, newlines) are correctly escaped per the RFC 4180 standard.
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