How is nesting expressed in the query string?

With square brackets, mirroring JavaScript member access: { "a": { "b": [1] } } becomes a[b][0]=1. Each level of object nesting adds a bracketed key, and each array index adds a numeric bracket, so the structure is fully recoverable on the way back.

What happens to null or empty values?

They produce an empty value in the query string (key= with nothing after). That is the faithful representation — a query string cannot encode "absence" more precisely than an empty field — so when rebuilding JSON the value comes back as an empty string rather than null. Drop such keys before sending if the server is strict.

Is the output URL-encoded?

The tool shows the logical key=value pairs; special characters in keys or values should be percent-encoded before putting them in a real URL. Encode the values (not the brackets) so the bracket structure stays intact and the server parses it correctly.

JSON to GET params — Guide

Flatten JSON into a URL query string (a[b][0]=1 style) and rebuild JSON from a query string or a full URL.

What it is and when to use it

HTML forms and many server frameworks encode structured data in the query string using bracket notation: a nested object { "b": { "c": 2 } } becomes b[c]=2, and an array { "list": [1, 2] } becomes list[0]=1&list[1]=2. This tool flattens JSON into that exact notation so you can drop a JSON payload straight into a URL, and parses a query string back into nested JSON when you receive one. It is the bridge between a clean JSON body and the bracket-encoded query strings that PHP, Express, Ruby on Rails and others expect.

Converts between JSON and GET query parameters: flatten nested objects into a query string such as a[b][0]=c, or rebuild JSON from it.

How to use it

Choose the direction: JSON → GET params or GET params → JSON
Paste the JSON or the query string
Copy the converted result

A worked example

Fill in sample JSON

{"a":1,"b":{"c":2},"list":[1,2]}

Copy this into the tool, or open JSON to GET params

Things that trip people up

Nesting levels and array indices are both expressed with square brackets, e.g. items[0][name]
Fields whose value is null, an empty array or an empty object produce an empty value

Questions people ask

How is nesting expressed in the query string?: With square brackets, mirroring JavaScript member access: { "a": { "b": [1] } } becomes a[b][0]=1. Each level of object nesting adds a bracketed key, and each array index adds a numeric bracket, so the structure is fully recoverable on the way back.
What happens to null or empty values?: They produce an empty value in the query string (key= with nothing after). That is the faithful representation — a query string cannot encode "absence" more precisely than an empty field — so when rebuilding JSON the value comes back as an empty string rather than null. Drop such keys before sending if the server is strict.
Is the output URL-encoded?: The tool shows the logical key=value pairs; special characters in keys or values should be percent-encoded before putting them in a real URL. Encode the values (not the brackets) so the bracket structure stays intact and the server parses it correctly.

Next steps

Open the JSON to GET params tool

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