How are arrays represented?

Use empty brackets like roles[]=admin&roles[]=editor, or numeric indices like roles[0]=admin.

Are values URL-decoded automatically?

Yes, percent-encoding and + for spaces are decoded when converting to JSON, and re-encoded going the other way.

Can I swap direction quickly?

Yes, the swap button flips the mode and carries over the current output as the new input.

Query String Converter

Convert between URL query strings and JSON, with nested bracket support.

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Query string

Input

JSON

Output

{
  "user": {
    "name": "Ada",
    "roles": [
      null,
      null,
      "editor"
    ]
  },
  "page": "2"
}

About the Query String Converter

Convert a query string into structured JSON (supporting bracket notation like a[b][]=1) or serialize JSON back into a query string, useful for debugging API requests and form submissions.

Examples

Nested query to JSON

user[name]=Ada&user[roles][]=admin

Output

{"user":{"name":"Ada","roles":["admin"]}}

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-06 · Runs entirely in your browser