What is the difference between Scrum and Kanban?

Scrum and Kanban are both Agile frameworks but differ significantly: (1) Iterations — Scrum uses fixed-length Sprints (1–4 weeks); Kanban has no fixed iterations, work flows continuously; (2) Roles — Scrum defines three roles (PO, SM, Developers); Kanban prescribes no specific roles; (3) Planning — Scrum has formal Sprint Planning; Kanban uses just-in-time replenishment of the board; (4) WIP limits — Kanban mandates WIP (Work in Progress) limits per stage; Scrum limits only the Sprint capacity; (5) Estimation — Scrum typically uses story points; Kanban focuses on flow metrics (cycle time, throughput); (6) Changes — Scrum protects the Sprint from scope changes; Kanban allows changes anytime; (7) Retrospectives — Scrum mandates Sprint Retrospectives; Kanban suggests but doesn't require them. Scrum is better for projects with defined sprint goals; Kanban for continuous flow work (support, maintenance, operations).