API Rate Limiting: Per User or Global?

hey folks, im architecting a new service and were thinking about api rate limiting. it seems like theres two main approaches: setting a global limit for all users, or setting individual limits per api key or user. a global limit is simpler to implement, but a single heavy user could impact everyone else. individual limits offer more fairness but could become complex to manage, especially with many users. whats your experiences with this? do you have a preferred strategy, or specific trade-offs youve encountered that led your decision