JSON to query string

What the conversion does

Write a flat JSON object as URL query parameters. Append scalar fields and array items using URLSearchParams encoding.

Worked example

Start with the input shown on this page: {"name":"Hello","message":["Welcome","Hello"]}. The tool produces: name=Hello&message=Welcome&message=Hello. Try the example first so you can compare the two representations. Then replace it with your own material. The result is plain text that you can copy into an editor, a test fixture or a request only after checking that its destination expects the same form.

Format rules and limits

A query string carries named parameters after the question mark of a URL. This tool accepts a leading question mark as an option but does not parse a complete URL. It follows URLSearchParams form-style rules: plus becomes a space, percent escapes represent UTF-8 bytes, and repeated keys are preserved as arrays when reading. Writing accepts a flat JSON object with strings, numbers, booleans or nonempty arrays of those scalar values. Everything in a query string is textual; a number written from JSON comes back as a string, so round trips do not preserve JSON types. Null, nested objects and empty arrays have no unambiguous representation here and are rejected. An encoded ampersand belongs to a value, whereas a literal ampersand separates parameters. Decode only after parsing the separators, and do not encode the already encoded result again.

Check the result

Keep the original beside the transformed text while you inspect it. Compare a small known case first, especially one containing punctuation, a non-ASCII character, a repeated value or an empty field relevant to your data. A readable output is not proof that the receiving program accepts the same schema or conventions. If you exchange data between applications, run the receiving parser and review a few records after import. Keep important source files under version control so changes are reversible. Processing takes place in your browser; this page does not send the pasted input to a conversion server. Browser memory and the clipboard still need ordinary care on shared devices.

The source and result have different roles even when they look similar. The method above defines the accepted subset rather than every extension of the named format. For a strict receiving system, try a small known case before changing many records. If validation fails, return to the original input and the first reported error; editing only the generated result can hide the cause.

Test query parameters with a value containing spaces, an ampersand and a non-ASCII character. Parse the generated string back and confirm repeated keys remain arrays. Compare textual values rather than JSON number or boolean types, which query strings cannot preserve. If you need a full URL, attach the resulting query after its path instead of pasting a whole URL into the query-only input.