Query String Parser & Builder
About Query String Parser / Builder
Query String Parser / Builder turns URL-encoded parameters into readable JSON and produces standards-friendly form query strings from flat JSON objects.
How it works
Parse a query or full URL
Everything before the question mark and after the fragment marker is ignored. UTF-8 percent escapes and plus-as-space form encoding are decoded strictly, with repeated names represented as arrays.
Optional scalar inference
Booleans, null and unambiguous JSON-style numbers can become typed JSON values. Leading-zero identifiers remain strings and blank values remain empty strings.
Build with explicit array style
JSON arrays can use repeated names, bracketed names or comma-separated values. Names and values are encoded independently and spaces use the conventional plus form.
Frequently asked questions
What happens to repeated parameters?
Parsing collects repeated names into an array. Building can repeat the name, append brackets or join array values with commas.
Does parameter order matter?
Input order and JSON property order are preserved by default. Enable sorting when you need deterministic name ordering.
Are nested objects supported?
There is no universal nested-query convention. Object values are encoded as compact JSON text so no structure is silently flattened.
Sources & last verified
The behaviour of this tool and the claims on this page were checked against the specifications below on . Everything runs in your browser, so the output you see is exactly what the engine produced.
Found a wrong result or an outdated claim? Report an error and it will be re-verified.