HANDLING COOKIES IS A MINEFIELD

Summary from the TLDR Web Dev newsletter

HTTP cookies are inconsistently handled across browsers and programming languages due to ambiguities in the RFC specifications. These inconsistencies are from mismatches between what servers should send and what browsers must accept, leading to situations where cookies containing perfectly valid characters for browsers are rejected by server-side code. This problem results in unpredictable behavior, with some systems silently dropping cookies and others percent-encoding values or failing completely.