JSON Key Extractor
Instantly parse nested JSON data and extract all keys, dot-notation paths, or JSONPath hierarchies. Filter, count frequencies, convert casing, and export clean schemas with zero latency.
Fetch JSON from URL
Enter any public JSON API endpoint or raw file URL (must have CORS enabled or support public access).
What Is a JSON Key Extractor
A JSON key extractor is a tool that reads through a JSON object, including every nested array and object inside it, and pulls out the key names. It saves you from manually scanning through raw JSON to figure out what fields exist, where they sit in the structure, and how they repeat across records.
WebToolar’s JSON Key Extractor does this directly in your browser. Paste in any JSON, and it returns the keys as a flat list, as dot notation paths like user.profile.id, or as JSONPath expressions like $.user.profile.id. Nothing gets uploaded to a server. Parsing happens on your device.
How to Extract Keys From a JSON File
- Paste your JSON into the input box. You can also upload a
.jsonor.txtfile, drag a file directly onto the input panel, or fetch JSON from a public API URL. - Pick an extraction scope: all unique keys, dot notation paths, JSONPath, root level keys only, or leaf keys only.
- Set the array path style. Choose wildcards (
items[*]), zero based index (items[0]), numeric dot notation (items.0), or skip array indexes entirely. - Apply a casing style if you need the keys reformatted into camelCase, snake_case, kebab case, uppercase, or lowercase.
- Sort the results alphabetically, by how often a key appears, or by depth in the hierarchy.
- Use the filter box to search by plain text or a regular expression.
- Switch to Tree view to browse the structure visually and click any node to copy its path.
- Copy the result or download it as .txt, .json, or .csv.
What This Tool Extracts
Unique keys: every distinct key name found anywhere in the JSON, with duplicates removed if you turn that option on.
Dot notation paths: the full location of each key, written the way you’d reference it in JavaScript, such as store.branches[*].contact.email.
JSONPath expressions: the same structure written in JSONPath syntax, useful if you’re working with tools like jq, JSONPath libraries, or API query filters.
Root level keys: just the first layer of the object, helpful for a quick overview of a large payload.
Leaf keys: only the keys that hold final values (strings, numbers, booleans), not the object or array containers around them.
Where This Is Useful
Working with an unfamiliar API: When you get a response from an API you haven’t used before, extracting the keys gives you the full shape of the data in seconds instead of scrolling through a huge JSON blob.
Writing documentation or a schema: Pull the leaf keys and their types to build a field list for a database schema, a TypeScript interface, or internal API docs.
Checking data consistency: Sort by frequency to see which keys show up in every record and which ones are missing from some. This catches inconsistent API responses or malformed exports before they cause bugs.
Auditing config files: Large nested config files (app settings, CMS exports, environment configs) get easier to review once you can see every key and its exact path.
Preparing data for another tool: If you need a list of field names to feed into a script, a spreadsheet, or a mapping table, export straight to CSV or a JSON array.
Frequently Asked Questions
What does a JSON key extractor do?
It scans a JSON object, including nested arrays and objects, and returns a list of every key it finds, either as plain key names, dot notation paths, or JSONPath expressions.
Is this tool free?
Yes. There is no sign up, no usage limit, and no cost.
Does it handle deeply nested JSON?
Yes. It recurses through objects and arrays at any depth, including arrays that contain other arrays or objects.
What’s the difference between dot notation and JSONPath?
Dot notation looks like user.profile.id. JSONPath adds a $ at the root and looks like $.user.profile.id. JSONPath is the format expected by JSONPath query libraries and some API tools; dot notation is closer to how you’d reference the value in JavaScript.
Can I get only the top level keys?
Yes. Set the extraction scope to “Root / Top Level Keys Only” and it will ignore anything nested deeper than the first layer.
Does my JSON get uploaded anywhere?
No. Parsing runs in your browser using JavaScript. Your data is never sent to WebToolar’s servers or anyone else’s.
Can I pull JSON straight from an API URL?
Yes, as long as the endpoint is public and allows cross origin requests (CORS). Paste the URL into the fetch option and the tool will load it directly.
Can I export the results?
Yes. Copy them with one click, or download as a plain text file, a JSON array, or a CSV with key, path, type, depth, and count columns.
Why Use WebToolar’s JSON Key Extractor
Most key extractor tools give you a flat list and stop there. This one adds the parts that actually matter for real work: JSONPath output, array path styles, casing conversion, frequency sorting, a clickable tree view, and four export formats, all processed locally so nothing you paste in ever leaves your browser.