Extract JSON Keys
Extract all keys from objects in JSON data. Runs entirely in your browser, so your data never leaves your device.
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Output
The result appears here as you type.
How to use Extract JSON Keys
- 1. Paste your JSON. Paste the JSON object or array you want to inspect. The tool walks every nested object, at every depth, pulling out each property name it finds along the way.
- 2. Set uniqueness and sorting. Turn on Unique keys only to list each key name once even if it appears in multiple objects, and Sort alphabetically to arrange the list for easy scanning instead of document order.
- 3. Copy the list of keys. Copy the resulting list, one key per line, and use it to review a schema, build a type definition, or check for typos across a large or unfamiliar JSON document.
When to use Extract JSON Keys
Extract JSON Keys pulls out every property name from a JSON document at any nesting depth, giving you a flat list of what fields actually exist. Use Extract JSON Keys when you need an inventory of a structure's shape without reading the whole document line by line.
- Reverse-engineering an undocumented API response. An endpoint returns a large, nested object with no documentation, and you want a quick list of every field name it contains before you start writing code against it.
- Auditing a config file for unused settings. You suspect a large JSON config has leftover keys nobody references anymore, and pulling a unique, sorted list of every key makes it easier to check each one against the codebase.
- Building a TypeScript interface by hand. You have sample JSON data and want to write a matching interface or type definition, starting from a complete list of the property names that need fields.
- Checking for inconsistent key naming. Different records in an array might use userId in one and user_id in another. A sorted, unique key list makes naming inconsistencies easy to spot at a glance.
Examples
List every key in a nested structure
Input
{"user": {"name": "Ada", "age": 36}, "active": true}Output
user name age active
About the Extract JSON Keys tool
Extract JSON Keys does its work locally, right in the browser. Extract all keys from objects in JSON data. There is no upload step, no queue and no account, and your data never travels over the network.
It belongs to the JSON Tools collection on EditSafely, a set of 90 small, focused JSON utilities that share the same instant, private workspace.
You can shape the output with 2 settings, including Unique keys only and Sort alphabetically, and the result refreshes the moment you change one. A worked example further down the page shows exactly what the tool produces for a real input.
Running locally also makes the tool fast and dependable: results appear as you type or drop a file, there is no server outage that can take it down mid-task, and confidential data can be processed without a second thought.
Frequently asked questions
Does Extract JSON Keys cost anything?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
No data leaves your device. The whole tool is JavaScript that runs inside your browser tab, so there is no upload, no server-side processing and no log of what you did. If you disconnect from the internet after the page loads, it keeps working.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
Nothing to install and no account needed. Open the page in any up-to-date browser, including on a phone or tablet, and the tool is ready.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.