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Query String to JSON

Turn a URL query string into structured JSON, including nested and repeated keys.

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Turn this off when your values are identifiers — a postcode or SKU with a leading zero would otherwise lose it.

Quick Tool Overview

The Query String to JSON converter decodes a URL query string into structured JSON, understanding nested a[b] keys, repeated keys, the a[] array form and percent-encoded UTF-8 bytes.

What it does
Parses a URL query string into structured JSON
You give it
A full URL or just the part after the question mark
You get back
Formatted JSON with nesting and arrays restored
Best for
Debugging form posts, tracking links and API requests
Developer Tools Free, unlimited use No sign-up Runs in your browser

About the Query String to JSON

A query string is a flat, percent-encoded blob that is hard to read once it grows past three parameters. This converter decodes it into JSON so you can actually see what is being sent — which is usually the first step in debugging a form post or a tracking URL.

It understands the conventions that make query strings structured. The a[b]=1 form becomes a nested object, a[]=1&a[]=2 and a repeated a=1&a=2 both become arrays, and percent-encoded bytes are decoded back to their characters, including UTF-8 sequences. Numeric and boolean-looking values are converted to real numbers and booleans by default, which you can turn off when the consuming system expects everything as a string.

Key features of the Query String to JSON

Nesting is restored

The a[b]=1 form becomes a real nested object rather than a key with brackets in its name.

Repeated keys become arrays

Both a=1&a=2 and a[]=1&a[]=2 produce an array, which is how every server-side framework reads them.

Full URLs accepted

Paste an entire address and everything before the question mark is ignored, so there is no trimming step.

Optional type detection

Numbers and booleans become real JSON values by default, or stay strings when your identifiers have leading zeros.

Correct decoding

Percent-encoded UTF-8 sequences decode back to their characters, and a plus sign becomes a space as the form-encoding rules require.

How to use the Query String to JSON

  1. 1

    Paste the query string

    A full URL, or just the part after the question mark — both work.

  2. 2

    Choose type handling

    Leave type detection on to get real numbers and booleans, or off to keep every value as a string.

  3. 3

    Read the JSON

    Nested and repeated keys become objects and arrays in the output.

  4. 4

    Copy the result

    The formatted JSON is ready to paste into a test or a request body.

Frequently asked questions

Yes. Anything before the question mark is ignored, so you can paste an entire address without trimming it first.

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