Versions

• Immutable Snapshots: Once published, Lambda function versions are fixed and cannot be modified.
• Usage: Useful for ensuring consistency and rollback scenarios.
• Creation: Created by publishing the function. Each version gets a unique ARN.

Aliases

• Pointers to Versions: Aliases link to specific versions and can be used for easy traffic management.
• Usage: Allows you to shift traffic between versions (useful for blue/green or canary deployments).
• Creation: Created and updated by pointing to specific versions, with the ability to manage traffic distribution.

In Summary:

• Versions = Fixed, unchangeable copies of your function.
• Aliases = Flexible names that can point to different versions and manage traffic.