Query String to JSON

A query string converter that turns the parameters in a URL into a readable JSON object, and builds a query string back from JSON. It decodes values, and treats repeated keys as arrays in both directions.

It runs locally in your browser, so the URLs you inspect, which can contain tokens or personal data, never leave your device.

A query string is the part of a URL after the question mark, like ?q=shoes&page=2, a list of key-value pairs that pass data to a page or API. They drive search results, filters, pagination and tracking.

When a key appears more than once, such as tag=a&tag=b, it becomes an array in the JSON so no values are lost, and a JSON array expands back into repeated parameters when you build the string.

You can paste a whole URL when converting to JSON: anything before the question mark is ignored, so you do not have to trim it first. This makes it quick to inspect the parameters of a link from your address bar.

Percent-encoded values are decoded when parsing so you can read them, and encoded again when building a query string so the result is valid, which keeps spaces and special characters correct.