Azure Cosmos DB is a versatile, high-availability distributed database offered by Microsoft on its cloud platform, Azure. Originally launched as DocumentDB in 2014 and rebranded in 2017, Cosmos DB supports multiple data models through various APIs, making it suitable for different use cases such as document-based, key-value, and graph databases. It offers tunable consistency levels, automatic scaling, and global distribution, all designed for easy management and high performance. While it excels in scenarios requiring schema flexibility and global reach, it can be expensive and may not be ideal for complex transactions or applications requiring strong schema enforcement. Cosmos DB is best suited for applications that value hands-off scalability and the ability to handle large, evolving datasets, but its cost and the potential for vendor lock-in are important considerations. Its integration with Azure and automated features make it a convenient option for developers, although traditional relational databases like PostgreSQL or SQL Server might be more appropriate for workloads needing complex joins or predictable cost structures.