Query String Builder & Parser

Edit URL query strings as a list of key/value pairs. Paste a URL or query string to round-trip through, switch between repeated-key, bracket-array, indexed-array, and comma-separated styles, and copy the encoded result back into your code.

Pairs

Key

Value

Array style: percent-encode keys percent-encode values use + for space (form-encoded) sort keys prefix with ?

pairs 0 encoded length 0 distinct keys 0

Query String

Paste a URL or query string here to load it into the editor

Code Snippets

JavaScript — URLSearchParams

Python — urllib.parse.urlencode

curl --get with --data-urlencode

About Array Styles

There is no single standard for repeating keys in a URL query string. RFC 3986 only describes the encoding rules; the structure of values is application-specific. Common conventions include:

repeat — Java Servlet, Express (default), Go net/url, browsers' URLSearchParams: ?tag=a&tag=b
bracket — PHP, Rails, qs library default: ?tag[]=a&tag[]=b
indexed — PHP/Rails for ordered or sparse arrays: ?tag[0]=a&tag[1]=b
comma — OpenAPI style: form, explode: false, some REST APIs: ?tag=a,b

Pick the convention your server expects. Mixing them on the same key (e.g. tag[]=a&tag=b) usually parses inconsistently — this tool will normalize the output to the chosen style on each rebuild.