Query String Tools
Build and parse URL query strings from key-value pairs.
Building and parsing query strings
Query strings encode key-value pairs after the ? in URLs. Builders serialize objects with proper encoding; parsers split pairs for debugging OAuth redirects and analytics parameters.
Duplicate keys, bracket notation, and plus-versus-percent20 semantics vary by framework. PHP-style array parameters differ from Node query parsers. Always decode then inspect rather than assuming flat maps.
UTM campaign parameters should stay lowercase for consistent analytics. Sensitive tokens in query strings belong in headers instead when possible because logs often capture full URLs.
Parse redirect URLs locally when they contain authorization codes or session IDs. Browser parsing keeps tokens off remote URL decoder services.
Reference Guide
QA tool - all processing runs locally in your browser. No data is sent to a server.
Operation: qs-build
Paste input, click Run, and copy the result. For two-input tools, fill both fields before running.
Example Input
q=devpipe page=1
A sample loads automatically when you open this tool. Use Load Sample to reset it.