Query String to JSON

What this tool converts

This tool parses a URL query string — with or without a leading ? or a full URL in front of it — into a JSON object using the browser's native URLSearchParams parser, which handles percent-decoding and + as space automatically. When a key appears more than once (?tag=a&tag=b), the tool detects the repeat and collects the values into a JSON array instead of overwriting the first one.

It accepts a bare query string (name=John&age=30), a string with a leading ? (?name=John), or a full URL (https://example.com/search?q=test) — the tool strips everything up to and including the first ? before parsing.

When to use it

Use it when debugging an incoming request, inspecting a redirect URL, or reverse-engineering what parameters a third-party API or tracking pixel expects — paste the raw query string from your browser's address bar or a server log and get a readable, structured JSON view instead of squinting at an encoded one-liner. It's also useful when writing tests: convert a real production query string to JSON once, then use that object as a fixture in code.

For the reverse direction — building a query string from a JSON object of parameters — use the companion JSON to Query String tool.

Example

Input ?name=John+Doe&age=30&tag=api&tag=backend converts to {"name": "John Doe", "age": "30", "tag": ["api", "backend"]} — the + decodes to a space, and the repeated tag key becomes an array. Note that age comes back as the string "30", not a number, since query strings have no native type information.