The query string is a tangle of parameters

A URL arrives with a dozen parameters in random order, some repeated, some URL-encoded. You need to read them, reorder them, or build your own without accidentally double-encoding something.

Parse and rebuild

The Query String Parser turns a query into key/value pairs, optionally sorts them, and lets you rebuild a clean string. Paste a messy query, read the structured list, and emit a tidy one for your request.

See the URL it lives in

The query is only part of the story. The URL Parser shows the query in context with the path and host, so you can confirm the whole link is correct before you use it. Parse the parameters, then verify the URL.

Common jobs

Constructing API calls with properly encoded parameters.
Normalizing a query for comparison or caching.
Inspecting what a third-party link actually passes.

Frequently Asked Questions

Why does my second parameter get lost?

Almost always an unencoded ampersand inside a value. The parser reads the ampersand as a separator, so one value silently becomes two parameters or one becomes none. Encode each value before assembling the string.

Does parameter order matter in a query string?

For the server usually not, but for caches and anything that signs a URL it does. Two links with identical pairs in different order are different strings, so normalise the order whenever a value is compared or signed.

When should I use the form mode instead of the URI mode?

Use form encoding when the string is a request body, because that is the convention servers expect. Use the looser URI mode for paths and fragments, where some symbols are allowed to stay literal.

Parse and build URL query strings