Azure Repos is a version control service provided by Microsoft Azure that allows software development teams to manage their code repositories securely and collaboratively. It is designed to host and manage Git and Team Foundation Version Control (TFVC) repositories for projects built using various programming languages and technologies.

Key features of Azure Repos include:

1. Git and TFVC Support: Azure Repos supports both Git and TFVC version control systems. Git is a distributed version control system widely used in modern software development, while TFVC is a centralized version control system often used in legacy projects.

2. Branching and Merging: Git repositories in Azure Repos enable developers to create and manage branches easily, facilitating collaboration and parallel development. Merging changes from one branch to another is also simplified, making it easier to integrate new features and fixes into the main codebase.

3. Code Reviews: Azure Repos allows developers to conduct code reviews, where team members can review proposed changes before they are merged into the main branch. This feature helps ensure code quality and adherence to coding standards.

4. Work Item Integration: Azure Repos can be integrated with Azure Boards, enabling a seamless connection between code changes and work items such as tasks, bugs, or user stories. This integration helps developers track their progress and associate code changes with specific tasks or requirements.

5. Security and Permissions: Azure Repos provides fine-grained access controls, allowing administrators to manage user permissions at various levels, such as repository, branch, or file level. This ensures that only authorized personnel can access sensitive code and repositories.

6. Build and Release Pipelines: Azure Repos can be integrated with Azure Pipelines, which enables developers to set up automated build and release processes for their code. This integration allows for continuous integration (CI) and continuous deployment (CD), streamlining the development workflow.

7. Extensions and Integrations: Azure Repos supports various extensions and integrations with third-party tools and services. This extensibility allows development teams to tailor their version control experience to their specific needs.

Azure Repos is often used in conjunction with other Azure DevOps services like Azure Pipelines, Azure Boards, and Azure Artifacts to create a comprehensive and efficient application development and delivery pipeline. It provides developers with a robust set of version control capabilities and helps teams collaborate effectively in building and shipping high-quality software.