Is this tool free to use?

Yes, this tool is completely free to use. No registration, subscription, or payment is required. All processing happens directly in your browser.

Does this tool upload data to a server?

No. All processing happens locally in your browser using JavaScript. Your data never leaves your device, ensuring complete privacy and security. The tool works even when offline.

Does this tool work on mobile devices?

Yes, this tool is fully responsive and works on all modern browsers including Chrome, Safari, Firefox, and Edge on desktop, tablet, and mobile devices.

Is an internet connection required to use this tool?

No internet connection is required after the page loads. Since all processing happens in your browser, you can use this tool offline once the page is loaded.

Is there a file size limit?

There is no server-side file size limit since files are processed locally in your browser. The only limitation is your device's memory (RAM). For very large files, we recommend processing them in smaller chunks.

🗂️ JSON Flattener

Free online JSON flattener. Convert nested JSON objects to flat key-value pairs. Customizable separator (dot, underscore), array index handling, null value strategy. Side-by-side comparison view. One-click copy or export. Perfect for data analysis, log processing, data warehouse import. Client-side only.

Enter JSON

Separator

Array

Null Values

Original JSON

Flattened Result

How to Use the JSON Flattener

Converting with the JSON Flattener takes just three steps:

Enter the Value to Convert
Type or paste the value you want to convert into the input area. The json flattener supports various input formats — just enter your data and the tool will recognize it automatically.
Select Source and Target Formats
Choose the source format and the target format from the available options. The tool supports bidirectional conversion where applicable. Your settings are applied instantly.
Get Your Conversion Result
The converted result appears in real time. Click "Copy" to copy it to your clipboard, or "Download" to save it. All conversion is done locally on your device with no server upload.

FAQ

JSON扁平化有什么用？

将嵌套JSON转为单层键值对，便于数据分析、导入数据库（如MongoDB、Elasticsearch）、日志处理等场景。

支持多深的嵌套？

支持任意深度的嵌套，包括对象嵌套、数组嵌套等复杂结构。

数组如何扁平化？

支持两种数组处理方式：使用数字索引（如items.0）或方括号索引（如items[0]）。