Status202

JSON Flattener

100% Private - Processed Locally

Paste nested JSON

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Processed locally in browser

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Flattened JSON
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What is it?


The JSON Flattener is a utility that takes a deeply nested JSON object and flattens it into a single-level dictionary. Nested keys are joined together using a delimiter (usually a dot . ).


When should you use it?


You should use this tool when you need to export complex, hierarchical API data into a flat CSV file, or when you are preparing a JSON payload to be ingested by a traditional relational SQL database that doesn’t support nested columns.


How does it work?


A recursive local JavaScript function walks through every branch of the JSON tree. When it encounters a nested object or array, it appends the parent key to the child key, creating a flat, one-dimensional output.


Example Input


{
  "user": {
    "profile": {
      "name": "Alice",
      "age": 30
    }
  }
}


Example Output


{
  "user.profile.name": "Alice",
  "user.profile.age": 30
}


How to Use This Tool


    

  1. Paste your nested JSON payload into the input editor.
    2. 

  2. The tool instantly traverses the JSON tree and flattens it, joining nested keys with dot notation.
    3. 

  3. Use the flattened output directly, or convert it to CSV for tabular analysis.
    4. 



Why use this offline tool?


Deeply nested JSON often contains complex, sensitive application state or user data. This flattener runs 100% locally on your machine, guaranteeing that your complex payloads remain completely private during processing.


Frequently Asked Questions
What does flattening JSON mean?▼
Flattening JSON takes a deeply nested object with multiple levels of hierarchy and compresses it into a single-level object. It achieves this by combining the nested keys using dot notation (e.g., `user.address.city`).
Does it handle arrays?▼
Yes, our flattener intelligently handles arrays by using bracket notation for the index. For example, the first item in an tags array becomes `tags[0]`.
Why is this tool useful?▼
It is incredibly useful for data analysts and engineers who need to convert complex NoSQL document data (like MongoDB or Elasticsearch responses) into a flat, tabular format (like CSV or SQL tables).