IAM roles are a way of granting temporary permissions to entities that need to access AWS resources, such as users, applications, or services. IAM roles allow customers to assign permissions to entities without having to create or manage IAM users or credentials for them. IAM roles can be assumed by different entities depending on the trust policy attached to the role. For example, IAM roles can be assumed by IAM users in the same or different AWS accounts, AWS services such as EC2 or Lambda, or external identities such as federated users or web identities. IAM roles can also be switched by IAM users to temporarily change their permissions. IAM roles are recommended for managing permissions for employees who often change teams, because they allow customers to define permissions based on job roles and responsibilities, and easily assign or revoke them as needed. IAM roles also reduce the operational overhead of creating, updating, or deleting IAM users or credentials for each employee or team change.