People who make a formal demand or condition for an agreement or contract.
Stipulators are usually seen as very serious and specific about what they want.
Examples:
The stipulators insisted on a specific delivery date.
The stipulators required a written guarantee.
The stipulators and the other party agreed on the terms.
The stipulators were very picky about the details.
The stipulators demanded a huge amount of money as a condition.
The stipulators made it clear that there would be no exceptions.