Free Online JSON to CSV Converter
Convert JSON arrays to CSV instantly — including nested objects. Automatic dot-notation flattening turns user.address.city into its own column. No sign-up, no tracking, 100% in-browser.
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Last updated: May 22 2026
Reviewed by the QuickTooly Team
JSON to CSV Converter Guide
Why Use QuickTooly.com's JSON to CSV Converter?
- Nested JSON flattening: Deeply nested objects are automatically expanded into dot-notation columns —
user.address.citybecomes its own CSV column. - Instant conversion: Paste your JSON and get a downloadable CSV in milliseconds, entirely in your browser.
- Private & secure: Your data never leaves your device — no server uploads, no logging.
- Flexible delimiters: Choose comma, semicolon, or tab to match your target application (Excel, Google Sheets, etc.).
- Array handling: Array values are joined into a single cell so spreadsheets stay clean and importable.
- Live row & column stats: See exactly how many rows and columns your CSV will contain before downloading.
- 100% free: No sign-up, no watermarks, no limits — generate as many CSVs as you need.
What is JSON to CSV Conversion?
JSON (JavaScript Object Notation) is the standard data interchange format for APIs and web services. CSV (Comma-Separated Values) is the universal format for spreadsheets, databases, and data analysis tools like Excel, Google Sheets, Pandas, and R. Converting between the two is a daily task for developers, data analysts, and business intelligence teams.
The challenge arises when JSON contains nested objects or arrays — flat CSV has no native concept of hierarchy. Most online converters fail or produce unreadable output. QuickTooly solves this with automatic dot-notation flattening, the same technique used by professional ETL pipelines.
How Nested JSON Flattening Works
Given this nested JSON object:
{ "name": "Alice", "address": { "city": "Prague", "zip": "10000" } }The converter produces these CSV columns:
name,address.city,address.zip Alice,Prague,10000
Each level of nesting is joined with a dot, making the column name self-documenting and importable by any spreadsheet tool. Turn off "Flatten nested objects" if you want to keep the raw JSON object string in a single cell instead.
Common JSON to CSV Use Cases
This converter is used every day by developers exporting API responses for analysis, analysts loading data into Excel or Google Sheets, data engineers preparing flat files for database imports, product teams exporting user records from REST APIs, and QA engineers verifying API payloads against expected tabular output.
How to Use This JSON to CSV Converter
Converting JSON to CSV with QuickTooly takes just seconds:
- Paste your JSON — a JSON array of objects works best; a single object is also supported
- Choose your options — toggle nested flattening and pick your preferred delimiter
- Click "Convert to CSV" — preview appears instantly with row and column counts
- Download or copy — save the file directly or copy to clipboard for pasting into a spreadsheet
Frequently Asked Questions
What JSON formats are supported?
The converter accepts a JSON array of objects (most common API response format) or a single JSON object. All keys across all objects are collected to build a complete header row — missing keys in some objects will produce empty cells.
How are nested objects handled?
When "Flatten nested objects" is enabled (default), nested objects are recursively expanded using dot-notation keys. When disabled, the raw JSON string of the nested object is placed in a single cell.
How are arrays inside JSON handled?
Array values are joined into a single cell using semicolons (e.g. tag1; tag2; tag3). This keeps the output importable into spreadsheets while preserving the original data.
Which delimiter should I use for Excel?
Use comma for English/US locale Excel. Use semicolon for European locales (French, German, Czech, etc.) where comma is the decimal separator. Tab works universally and avoids all delimiter conflicts when values may contain commas.
Is there a file size or row limit?
There is no enforced limit — the conversion runs entirely in your browser, so the only constraint is your device's available memory. Practically, JSON files up to several megabytes convert in under a second on any modern machine.
Is my JSON data sent to a server?
No. QuickTooly's JSON to CSV converter is entirely client-side. Your JSON is parsed and converted locally using JavaScript in your browser — nothing is transmitted to any server.