JSON Key Extractor — All Property Names
Recursively list every object property name found anywhere in a JSON tree, sorted uniquely.
How it works
- 1Paste or type your text in the input field
- 2Click "Extract keys" — processing happens in your browser
- 3Copy the result or download as a text file
What to do next
About JSON Key Extractor
JSON Key Extractor is the kind of utility you bookmark and reach for when you need it. Recursively list every object property name found anywhere in a JSON tree, sorted uniquely. It loads quickly, works on any modern browser, and produces a result you can download or copy in a single click.
The heaviest users of JSON Key Extractor tend to be devops engineers crafting one-liners, site reliability engineers triaging logs and QA engineers writing repro cases. Each group brings slightly different expectations to the tool, but the same single-page architecture serves every one of them with the same response time.
The execution path is auditable from the page itself: open developer tools, switch to the Network tab, run a job. The requests you see are static-asset GETs for the engine and the page resources. The actual work is JavaScript code running against the bytes already in your tab's memory.
JSON Key Extractor is implemented on top of standard browser APIs. Inputs are read from the file picker or drop zone, decoded in the browser, processed, and re-encoded into the output format. Files up to 0 MB are well within the comfort zone of any modern browser.
Reach for JSON Key Extractor when you need a predictable result on a single file. The page works on the first visit, the controls are visible without a menu, and the output is delivered the moment the engine finishes.
JSON Key Extractor is intentionally narrow in what it does, which makes it easy to slot into a longer workflow. Take its output, hand it to whichever next tool fits the job, and JSON Key Extractor stays out of your way until the next time you need it.
The output handed back by JSON Key Extractor is the output file. If you would prefer to keep the result in the browser instead of downloading it, you can copy it from the result panel and paste it directly into another tab — useful when the next tool in your workflow expects pasted text rather than a file.
The 0 MB ceiling on input size is the only fixed limit. Output files are produced in standard formats that every common viewer recognises, and the tool runs the same way regardless of how many times you have used it during the session.
JSON Key Extractor is honest about scope: it handles a single, well-defined developer utility step. Specialist edge-case work — uncommon formats, very large inputs, or pipelines that need scripting — is what dedicated desktop apps are for. This page handles the common case quickly.
Some context on why JSON Key Extractor exists in this form: modern File APIs, high-performance JavaScript engines, and well-maintained open-source libraries now make it possible to perform developer utility work entirely in the browser. JSON Key Extractor is built on top of that capability, which is why a single page can host the full pipeline.
Tips from users who reach for JSON Key Extractor regularly: process one input first to confirm the settings produce what you expect before committing to a batch; treat the page as the working surface and avoid leaving large jobs running in a backgrounded tab where the browser may throttle JavaScript; and if a particular file fails, check whether the source is intact by opening it in its native viewer — most "tool errors" are actually input errors.
If the result is not what you expected, the most common causes are easy to check. Confirm the input is under the 0 MB ceiling — files just above the cap fail silently because the engine refuses to allocate the buffer. Confirm the input is one of the supported formats. And if the page itself feels slow, try closing other heavy tabs to free up memory; the engine runs in your browser, so it competes for the same resources as everything else open.
JSON Key Extractor produces deterministic output: the same input plus the same options always produces the same result. That predictability matters when the result has to match an upstream specification or be reproducible later.
JSON Key Extractor is one of many single-purpose tools in the catalog. Each is built around the same single-page model. Use this one, close the tab, and come back the next time you need the same job done. None of the tools require prior knowledge of the others — each page is self-contained.
How it works
- 1Open the JSON Key Extractor workspace above. The interface is a single page, so there is nothing to navigate.
- 2Drop a developer file onto the upload area, or click to pick one from your device.
- 3Tweak the controls if the defaults are not quite right for your input. The options are kept short and labelled in plain language.
- 4Trigger processing. standard browser APIs reads your input, applies the transformation, and writes the result back into the page.
- 5Grab the output as soon as the run completes. You can also copy the result instead of downloading if the next tool in your workflow accepts pasted input.
- 6Run additional jobs as needed. The same controls and defaults apply on every run.
Common use cases
- Convert between data formats while wiring up an integration using JSON Key Extractor.
- Encode binary content for transport in a JSON body.
- Validate a config blob before pushing to staging.
- Hash a string for a quick reproducibility check.
- Pretty-print a minified blob during incident triage.
- Inspect a regex against a test string before committing it.
- Generate a quick fixture without leaving the browser.
- Inspect a payload during local development without writing a script.
- Compare two API responses to spot a regression.
FAQ
Are duplicate keys deduplicated?
Yes — property names are stored in a Set and printed once each in sorted order.
Do array indexes appear?
No — only object keys are listed; array positions are not treated as named keys.
Is traversal local?
Yes — the walker never sends your JSON to a server.
What about very deep trees?
Deep recursion may hit engine limits; consider chunking or filtering for extreme depths.
Can I export CSV?
Output is plain newline-separated text you can paste into spreadsheets or scripts.
Does order reflect document order?
Output is sorted alphabetically for predictable diffs, not insertion order.
Does JSON Key Extractor match what professional tools produce?
JSON Key Extractor is built on standard browser APIs, which is the same class of engine used by professional developer utility pipelines. For deterministic operations, the output is byte-identical to what an equivalent CLI run would produce; for operations involving a codec or a model, the result is well within the range of what comparable tools generate. If you have a specific reference output you need to match, run a small test job first to confirm the configuration produces what you expect.
Does JSON Key Extractor require a browser extension or plug-in?
No installation is needed. JSON Key Extractor runs as a normal web page, with no browser extension, no native helper, and no separate desktop client to download. That is partly a privacy choice — extensions can request broad permissions, while a regular page is sandboxed by default — and partly a convenience one: you can use JSON Key Extractor on any computer you have temporary access to without leaving anything installed on it.
How do I run JSON Key Extractor over a folder of files?
JSON Key Extractor processes one input at a time by design — it keeps memory usage predictable on lower-end devices and makes results easier to verify. To handle a folder, run the tool once per file; the page stays loaded between runs and remembers your last-used settings, so the second run is essentially instant.
Can I self-host JSON Key Extractor for my team?
JSON Key Extractor is a static page running an open-source engine in your browser, so a typical corporate firewall does not get in the way as long as it allows JavaScript to load from Favtoo. For teams that need to host it themselves on an internal network, the underlying engine (standard browser APIs) is open-source and can be packaged into a private build with the same behaviour. Reach out via the Contact page if that is something you are exploring.
Does JSON Key Extractor work in Safari, Firefox, Chrome and Edge?
JSON Key Extractor works in any modern browser released in the last few years — Chrome, Edge, Firefox, Safari, Brave, Arc and the major Chromium derivatives are all supported. The underlying engine relies on widely-supported web APIs, so there is nothing exotic to install. If you are on a very old browser version and the tool fails to load, updating to the latest release of your preferred browser is the only fix needed.
How many times per day can I use JSON Key Extractor?
Inputs are capped at 0 MB per file, which keeps memory usage stable across phones, tablets and older laptops. You can run JSON Key Extractor as often as you need; every run produces a full-quality result.
Are there any hidden fees with JSON Key Extractor?
JSON Key Extractor is free to use. The processing runs in your browser, which keeps the per-user cost low enough that the tool can be offered openly. The download is the same file the engine produced — you can use it for as many runs as you need.
Does JSON Key Extractor ask for any browser permissions?
JSON Key Extractor only needs the standard web platform — file picker access for the inputs you choose to load, and optionally clipboard access if you copy the result rather than downloading it. There is no microphone, camera, geolocation or background-permission request, because none of those are needed for the work the tool does.