1. Deployment Methodology: AWS CodeDeploy is a fully managed deployment service that automates the deployment of applications to various compute services, whereas Packer is a tool for creating identical machine images for multiple platforms from a single source configuration.
2. Scope: CodeDeploy focuses on application deployments to a variety of service types within AWS, such as EC2 instances, Lambda serverless functions, and ECS services, while Packer is primarily focused on building machine images for platforms like AWS, Azure, and VirtualBox.
3. Real-time vs. Pre-configured images: With CodeDeploy, deployments happen in real-time based on the current state of the target environment, adjusting dynamically to scale up or down, whereas Packer generates pre-configured machine images that can be launched when needed without real-time adjustments.
4. Continuous integration: CodeDeploy seamlessly integrates with other AWS services like CodePipeline for continuous integration and continuous deployment (CI/CD), ensuring a streamlined software delivery process, whereas Packer is more commonly used in the initial stages of setting up infrastructure.
5. Customization level: Packer allows for a high level of customization with templates and provisioners to configure machine images exactly as needed, while CodeDeploy is more focused on deploying applications based on defined deployment configurations without as much flexibility in infrastructure creation.
6. Automation capabilities: CodeDeploy provides extensive automation capabilities for managing deployments and monitoring progress through various integrations, whereas Packer focuses more on the automation of image creation rather than deployment processes.

In Summary, the key differences between AWS CodeDeploy and Packer lie in their deployment methodology, scope, real-time capabilities, integration with CI/CD tools, customization levels, and automation capabilities.