Explore Tools
Six standalone JSON tools that run in your browser. What each one does, its options, and the things worth knowing before you trust a result.
Six JSON tools are live at /tools. Each is a single page: paste on the left, read the answer on the right. Results update as you type, so there is no Run button. You don't need an account, and nothing you paste leaves the tab or is saved.
Finding a tool
The search box on /tools matches every word you type, in any order, against tool names, summaries and the phrases people search for. "beautify json" and "json beautify" find the same tool. A search also lists matching tools that are planned but not built yet, under More API & dev tools. Those have no page yet.
Controls every tool shares
- Open file reads a
.jsonor.txtfile from your disk. You can also drag a file onto the input. - Clear empties the input.
- Copy puts the result on your clipboard. Some tools also have Download.
- Below each tool there is an About section and a Questions list. Read them when a result surprises you.
- Next to this one, at the foot of the page, links to related tools.
The tools
| Tool | Address | What it does | Options |
|---|---|---|---|
| JSON formatter and validator | /tools/json-formatter | Indents, minifies or sorts JSON. Errors give the line and column. Duplicate keys are listed | Indent: 2 spaces, 4 spaces, Tabs or Minified. Sort keys. Strict JSON |
| JSON diff | /tools/json-diff | Compares two documents by structure, so key order and whitespace are not counted as changes | Arrays: By position, By key or As a set. By key matches on a field you name, id by default |
| JSONPath tester | /tools/jsonpath-tester | Runs a JSONPath as you type and shows the exact path of every match | Click a result path to narrow the query to it |
| JSON flatten and unflatten | /tools/json-flatten | Turns nested JSON into dotted keys and back, without losing empty objects or arrays | Direction, Separator, Indices, and As: Flat JSON, CSV or Environment |
| JSON size profiler | /tools/json-size-profiler | Shows which keys and arrays take up the bytes, how much is field names, and the real gzipped size | None |
| NDJSON viewer | /tools/ndjson-viewer | Reads JSON Lines one record at a time. A broken line is reported and the rest still load | Filter by a word, or by a JSONPath that starts with $. Copy as array, Download |
Things worth knowing
- Big numbers are kept as written. The formatter does not round an id like
12345678901234567890, which most formatters quietly do. - The formatter forgives by default. Comments, trailing commas, single quotes and unquoted keys are fixed, and each fix is listed. Turn on Strict JSON to have them reported as errors instead.
- Duplicate keys are reported, not hidden. The last value wins, as it does in JavaScript, but you get the key, its path and both line numbers.
- A key that already contains the separator can't be flattened safely. A key named
a.band a keybinside an objectaflatten to the same thing. The flatten tool lists these collisions. Choose a different separator to fix them. - The NDJSON viewer reads up to 5,000 records and tells you when it stopped early. Filter first if your file is larger.
- The JSONPath tester runs JSONPath only. It does not run jq or JMESPath, which are different languages.
- The gzipped size is measured, not estimated. If your browser lacks the compression API, the figure is left out.
From a tool to the API Map
If what you pasted is an OpenAPI, Swagger or Postman file, each tool offers a link to open it in the API Map instead. The JSON diff, for example, compares documents. To compare two versions of an API by operation and parameter, use the API diff.