Azure SQL Database vs Cosmos DB

	Azure SQL Database	Azure Cosmos DB
Type of Database	Relational database	NoSQL database
Features	Has several SQL deployment options for different kinds of workloads – SQL databases, SQL managed instances, SQL virtual machines.	Delivers single-digit millisecond response times and instant scalability.
Storage Size	100 TB for SQL database 8 TB for SQL managed instance 256 TB for SQL virtual machine	Unlimited storage per database and container.
Availability	SQL database – 99.995% availability SQL managed instance and SQL virtual machine – 99.99% availability	Single-region – 99.99% Multi-region – 99.999%
Backups	With long-term backup retention policy, database backups are automatically retained in separate Azure Blob storage containers (up to 10 years).	Periodic backup mode (default) – the backup is created at a periodic interval and the data can be restored by creating a request with the support team. Continuous backup mode – allows you to restore your data to any point of time within the last 30 days.
Encryption	Supports encryption at rest for Microsoft-managed service side and client-side encryption. Supports Transparent Data Encryption for server encryption. The Azure SQL Database supports RSA 2048-bit customer-managed keys in Azure Key Vault.	CosmosDB encrypts data at rest and the keys are managed by Microsoft. You can also use your own encryption keys (customer-managed keys).
Maintenance	Supports serverless compute tier for Azure SQL Database.	Supports serverless containers that can serve thousands of requests per second.
Pricing	The resources are billed hourly at a fixed rate based on the service tier and compute size you choose.	The cost of all database operations is normalized and expressed as request units (RU). Specific billing options for each database operation models: Provisioned Throughput and Serverless.
Use cases	Azure SQL is based on SQL Server engine, you can easily migrate applications and continue to use the tools, languages, and resources that you’re familiar with.	Azure Cosmos DB is used for web, mobile, gaming, and IoT application that needs to handle massive amounts of data, reads, and writes at a global scale.