JSON stands for JavaScript Object Notation. It is a text format for representing data that different applications can exchange. You may see it in API responses, configuration exports and saved application records. Although the name includes JavaScript, many programming languages can read and write JSON.
Use the U18-CHAN Json Viewer alongside this guide.
Objects, arrays and values
An object uses braces and stores named properties. An array uses square brackets and keeps values in order. Values can be strings, numbers, booleans, null, objects or arrays. A simple object might contain a title and an array of tool names. Nested objects make relationships visible without requiring a table for every part.
Follow strict syntax
Property names and string values need double quotes. Separate items with commas and do not add a trailing comma after the last item. Standard JSON does not allow comments, functions or undefined values. Copying a JavaScript object literal directly into a JSON field can fail because the two syntaxes are related but not identical.
Read a document with the viewer
Paste a harmless example into JSON Viewer and expand the resulting tree. Compare the keys and values with the original input. Use JSON Formatter for an indented text version and JSON Validator for a syntax check. These tools do not execute the pasted document as source code.
Remember data-specific limits
A syntactically valid object can still contain a missing field or a value your application rejects. Check the application’s schema separately. Very large numeric identifiers can also lose precision in a JavaScript parse; exact numeric handling may require strings or a different parser. Do not treat a successful viewer result as proof that all downstream checks will pass.
A simple finishing check
Keep the original input, inspect the result and confirm that it fits the destination where you plan to use it. If a result looks unexpected, try a small harmless example and read the limitations on the tool page before proceeding.
Browse all free U18-CHAN tools to continue, or report a problem with a clear description of the tool and browser.