Project constraints refer to any limitations or boundaries that restrict the planning and execution of a project.
Time, cost, and scope constraints are the three major ones used for managing projects successfully: time constraint refers to a fixed deadline or timeline in which all tasks and deliverables must be completed within.
Cost constraint refers to your allocated budget that should not change unexpectedly during its lifespan; scope constraint refers to your intended objectives, deliverables, or features the project is expected to achieve; effectively managing these constraints is key in order to meet stakeholder expectations and ensure project success and meeting stakeholder expectations from its stakeholders.