Free Query String to JSON Converter
for developers.

Convert query strings to JSON instantly with this free online query string to JSON converter. Parse URL parameters, repeated keys, and full URLs directly in your browser.

Paste your query string

Generated JSON

{
  "name": "John Doe",
  "city": "Tokyo",
  "role": "developer",
  "tag": [
    "frontend",
    "typescript"
  ]
}

Supported

Query strings starting with ?
Raw query parameter strings
Full URLs with query parameters
Repeated keys such as tag=a&tag=b
Automatic URL decoding
Live query string to JSON conversion

Automatically handled

Leading question marks are removed automatically
Full URLs are parsed automatically
Repeated query parameters become JSON arrays
Percent-encoded values are decoded automatically

Not supported yet

Automatic boolean or number type inference
Nested query syntax parsing such as bracket notation
Custom decoding rules

Free online query string to JSON converter

This tool converts query strings into formatted JSON instantly in your browser. It works with raw URL parameters, full URLs, and repeated keys, making it useful for frontend development, backend debugging, API testing, and general web tooling.

Developers often need to inspect query parameters quickly, transform URL params into JSON objects, or debug routing and search parameter logic. This converter gives you a fast way to do that without writing custom parsing code.

The conversion runs locally in your browser. Your query string is not uploaded, stored, or sent anywhere.

Example

?name=John%20Doe&city=Tokyo&tag=frontend&tag=typescript

Paste this query string into the converter above to instantly generate the equivalent JSON output.

Convert query strings to JSON online

Use this converter to transform URL parameters into readable JSON for JavaScript, debugging, routing logic, test fixtures, and development workflows.

Common use cases

Inspect URL search params during frontend development
Convert repeated query keys into JSON arrays
Debug API query parameters quickly
Parse full URLs into structured parameter objects

How it works

The converter reads your query string, removes the leading question mark when needed, parses the parameters using the browser URL API, and returns a formatted JSON object.

If the same parameter appears multiple times, the tool groups those values into an array. That makes repeated keys much easier to inspect and reuse in code.

Percent-encoded values are decoded automatically, so strings like John%20Doe become readable output immediately.

FAQ

What is a query string to JSON converter?

A query string to JSON converter transforms URL parameters into a structured JSON object that can be inspected, copied, and reused in code.

Can I paste a full URL instead of just the query string?

Yes. This tool accepts full URLs and automatically extracts the query string before converting it to JSON.

What happens with repeated query parameters?

Repeated keys such as tag=a&tag=b are converted into JSON arrays.

Is this query string to JSON tool safe?

Yes. The conversion happens locally in your browser and your data is not uploaded.

More developer tools

DevWrench provides a growing collection of browser-based developer tools including JSON utilities, converters, encoders, and debugging helpers.

Free Query String to JSON Converterfor developers.