A query string is the part of a URL commonly used to pass named parameters after a question mark. Parameters can control a request, select a resource or carry authentication-related information according to the server's design. Their meaning is implementation-specific, and altering them can change the response or invalidate an otherwise working private address.
A practical example
An order page can read a month parameter to preselect a term, while a media endpoint can use a token parameter for access. Those similar-looking address components have different purposes and should not be edited or shared under one assumption.
A common misunderstanding
Do not assume query parameters are harmless tracking text or that rearranging and deleting them is always safe. A private service URL may depend on exact values or signatures for authorization.
Related terms
Stable technical definition. Editorial approach