Need to simplify a nested JSON object? Use this free JSON Flatten Tool to flatten deeply nested JSON into easy-to-read key-value paths directly in your browser.

There is no login, no registration, and no software installation required. Paste your JSON, choose your preferred options, and flatten it online in seconds.

You can also unflatten JSON, format JSON, minify JSON, work with arrays, customize delimiters, and view your results in Raw, Table, or Tree format.

What Is a JSON Flatten Tool?

A JSON Flatten Tool converts a nested JSON object into a single-level structure where nested properties are represented as paths.

For example, this JSON:

{
  "user": {
    "name": "John",
    "address": {
      "city": "New York"
    }
  }
}

can be represented in flattened form as:

{
  "user.name": "John",
  "user.address.city": "New York"
}

This type of JSON transformation is useful when nested data is difficult to inspect or when an application requires simple key-value paths.

With WebToolar’s JSON Flatten Tool, you can control how those paths are generated instead of being limited to one fixed format.

Flatten Nested JSON Online

If you need to flatten JSON online, you don’t have to manually rewrite every nested property. Paste your JSON into the input editor and select Flatten JSON.

The tool supports deeply nested objects and provides options for controlling the flattening process. You can also choose a maximum depth when you only want to flatten part of a JSON hierarchy.

This can be particularly useful for developers working with:

• Nested API responses
• Configuration files
• JSON data exports
• Application settings
• Database-style key-value data
• Complex JavaScript objects
• Data transformation workflows

JSON Unflatten Tool

Flattening is not always the end of the process. Sometimes you need to turn flat key paths back into a nested JSON structure.

That’s why the tool also includes JSON Unflatten functionality.

For example:

{
  "user.name": "John",
  "user.email": "[email protected]",
  "user.address.city": "New York"
}

can be reconstructed into:

{
  "user": {
    "name": "John",
    "email": "[email protected]",
    "address": {
      "city": "New York"
    }
  }
}

The unflatten function reads the key paths and rebuilds the JSON hierarchy using your selected delimiter.

This makes the tool useful for both directions of JSON transformation: nested JSON to flat JSON and flat JSON back to nested JSON.

Customize JSON Path Delimiters

Different applications and data workflows use different naming conventions. The tool lets you choose how nested paths should be separated.

Available delimiter styles include:

• Dot: user.name
• Slash: user/name
• Underscore: user_name
• Double underscore: user__name
• Dash: user-name
• Colon: user:name
• Custom separators

You can also enter a custom delimiter when the available options do not match your workflow.

This gives you more control over the final flattened JSON structure.

Handle JSON Arrays With Different Path Styles

Arrays can make JSON flattening more complicated because each item needs a path or index.

The JSON Flatten Tool supports several array path styles, including:

items.0.name

items[0].name

and bracket-based representations.

You can also choose to preserve arrays instead of flattening them.

This is helpful when working with API responses containing lists of users, products, orders, categories, or other repeated objects.

Control Flattening Depth

Not every JSON document needs to be completely flattened.

For example, you may want to flatten only the first few levels of a large JSON structure while keeping deeper objects intact.

The tool provides depth controls ranging from the root level through multiple nested levels, as well as an unlimited-depth option.

This makes the transformation more flexible for large or complicated JSON documents.

View Flattened JSON as Raw, Table, or Tree Data

Understanding a large JSON result can be difficult when everything is displayed as plain text. The tool provides multiple ways to inspect the output.

You can switch between:

Raw View
See the formatted JSON output directly.

Table View
Inspect flattened paths, data types, and values in a structured table.

Tree View
Explore the JSON hierarchy visually and expand or inspect nested nodes.

The table view identifies the flattened key or path, its type, and its value, while the tree view provides a hierarchical representation.

Beautify and Minify JSON

The tool can also help clean up JSON before or after a transformation.

Use Beautify when you want properly formatted JSON with readable indentation. Use Minify when you want to remove unnecessary whitespace and create a compact JSON representation.

This is useful when moving JSON between development tools, APIs, configuration files, or documentation.

Upload a JSON File or Load JSON From a URL

You don’t always have to copy and paste your JSON manually.

The input area supports loading a .json or .txt file, and the tool also provides an option to fetch JSON from a public URL or API endpoint when the endpoint supports the required browser access.
This can make it easier to work with existing JSON files and publicly accessible API responses.

Export and Copy Your JSON Results

After processing your data, you can quickly copy the result or download it for later use.

The output area includes options for:

• Copying the transformed JSON
• Downloading JSON
• Downloading CSV
• Swapping the output back into the input editor

These features are useful when JSON transformation is part of a larger development or data-processing workflow.

Who Can Use a JSON Flatten Tool?

A JSON flattening tool can be useful for anyone who regularly works with structured data.

Developers

Developers can flatten API responses, inspect nested objects, prepare test data, and transform JSON structures during development.

API Engineers

API responses often contain several levels of nested objects and arrays. Flattening those responses can make individual properties easier to inspect.

Data Analysts

Flat key-value structures can sometimes be easier to review or prepare for further processing and analysis.

QA and Testing Teams

Flattened paths can make it easier to identify individual JSON properties when testing API responses and application data.

Students and Beginners

If you’re learning JSON, JavaScript objects, APIs, or data structures, seeing a complex nested object represented as individual paths can make the relationship between parent and child properties easier to understand.

How to Flatten JSON Online

You can flatten JSON in a few simple steps:

1. Paste or load your JSON into the input editor.
2. Select your preferred delimiter and array style.
3. Choose a maximum depth if required.
4. Select the desired output format and sorting option.
5. Click Flatten JSON.
6. Review the result in Raw, Table, or Tree view.
7. Copy or download the transformed data.

The tool validates the JSON before processing it, so invalid JSON syntax is reported instead of being processed as valid data.

JSON Flattening vs. JSON Unflattening

The two operations solve opposite problems.

Operation	Purpose
Flatten JSON	Converts nested JSON into flat key paths
Unflatten JSON	Rebuilds nested JSON from flat key paths
Beautify JSON	Formats JSON for easier reading
Minify JSON	Removes unnecessary whitespace
Table View	Displays paths, types, and values in a table
Tree View	Displays JSON in a hierarchical structure

Using both flatten and unflatten together can be useful when testing transformations or moving data between systems that expect different JSON structures.

FAQs: JSON Flatten Tool

What does flattening JSON mean?

Flattening JSON means converting nested objects and arrays into a simpler structure where each nested property is represented by a path such as user.address.city.

How do I flatten JSON online?

Paste your JSON into the JSON Flatten Tool, choose your preferred path and array settings, and click Flatten JSON. The transformed result will appear in the output area.

Can I unflatten JSON?

Yes. The tool can convert flattened key paths back into a nested JSON hierarchy using the selected delimiter.

Can I flatten deeply nested JSON?

Yes. The tool supports unlimited flattening depth as well as configurable depth limits, allowing you to decide how far the JSON hierarchy should be flattened.

How are arrays handled when flattening JSON?

Arrays can be represented using dot indexes, bracket indexes, or other supported styles. You can also choose to preserve arrays rather than flattening them.

Can I use a custom delimiter?

Yes. In addition to common dot, slash, underscore, dash, and colon separators, you can enter a custom delimiter.

Can I format JSON with this tool?

Yes. The Beautify option formats valid JSON with readable indentation, while Minify creates a compact JSON representation.

Can I download flattened JSON?

Yes. The output can be copied and downloaded, including JSON and CSV output options.

Try the Free JSON Flatten Tool Online

When nested JSON becomes difficult to read or work with, flattening can provide a much simpler view of the data. Instead of manually converting every nested property, use the JSON Flatten Tool to transform, inspect, format, and convert your JSON in one place.

Whether you need to flatten nested JSON, unflatten key-value paths, handle arrays, customize delimiters, format JSON, or export transformed data, the tool provides the controls needed for a practical JSON transformation workflow.