The main difference between Azure DevOps Services and Azure DevOps Server is the hosting model. Azure DevOps Services is a cloud-based service hosted by Microsoft, while Azure DevOps Server is an on-premises solution that you install and manage yourself. The choice between the two depends on your organization's specific needs and preferences.Azure DevOps Services and Azure DevOps Server are both powerful tools for managing the software development lifecycle, but they have some key differences.Azure DevOps Services, formerly known as Visual Studio Team Services (VSTS), is a cloud-based platform that provides a comprehensive set of tools and services for managing the entire software development process. It offers features such as version control, build and release management, project tracking, and collaboration tools. Azure DevOps Services is hosted and managed by Microsoft, which means you don't have to worry about infrastructure or maintenance.On the other hand, Azure DevOps Server, previously known as Team Foundation Server (TFS), is an on-premises version of Azure DevOps Services. It allows you to install and manage the entire Azure DevOps platform within your own infrastructure. This gives you more control over your data and allows you to customize the platform to meet your specific requirements. Azure DevOps Server is ideal for organizations that have strict data security or compliance requirements, or for those who prefer to have complete control over their development environment.