1. Key Difference 1: Integration with Development Environment: AWS CodeCommit is a fully managed source control service that is integrated with other AWS services, making it easy to collaborate on code during the development process. On the other hand, IntelliJ IDEA is an integrated development environment (IDE) that provides a complete set of tools and features for software development. It offers integration with various version control systems, including Git, allowing developers to interact with CodeCommit directly from the IDE.

2. Key Difference 2: Hosting and Access Control: AWS CodeCommit provides a secure and scalable hosting solution for Git repositories, allowing multiple developers to collaborate on code and manage access control using AWS Identity and Access Management (IAM). In contrast, IntelliJ IDEA does not provide hosting for repositories but offers features to clone, push, pull, and manage repositories hosted in CodeCommit. Access control in IntelliJ IDEA is typically managed at the repository level rather than through IAM.

3. Key Difference 3: Collaboration and Code Reviews: CodeCommit offers built-in features for collaboration and code reviews, such as pull requests, which allow developers to review and comment on code changes before merging them into the main branch. IntelliJ IDEA, on the other hand, provides integrated tools for code inspections, version control history, and code navigation, but lacks the dedicated collaboration features offered by CodeCommit.

4. Key Difference 4: Scalability and Availability: AWS CodeCommit is a highly scalable and available service, with automatic replication and data redundancy across multiple availability zones. This ensures that developers can access their code repositories without any downtime. IntelliJ IDEA, on the other hand, relies on the availability and scalability of the underlying version control system, such as CodeCommit, and does not provide the same level of scalability and availability as a dedicated service like CodeCommit.

5. Key Difference 5: Pricing and Cost: AWS CodeCommit follows a pay-as-you-go pricing model, where users are charged based on the number of active users, the amount of data transfer, and the storage used. IntelliJ IDEA, on the other hand, is a commercial IDE and requires a license to use. The cost of IntelliJ IDEA is typically based on a subscription or perpetual license model, depending on the edition and usage requirements.

6. Key Difference 6: Cross-Platform Compatibility: IntelliJ IDEA is a cross-platform IDE, available for Windows, macOS, and Linux, providing a consistent development environment across different operating systems. CodeCommit, as a cloud-based service, can be accessed from any platform using a web browser or Git client, ensuring compatibility across different development environments and platforms.

In Summary, AWS CodeCommit is a fully managed source control service integrated with other AWS services, providing hosting, access control, collaboration features, scalability, and a pay-as-you-go pricing model. IntelliJ IDEA, on the other hand, is an integrated development environment that facilitates code development and management, with features for integrating with CodeCommit and other version control systems, collaboration tools, cross-platform compatibility, and commercial licensing.