Azure Blob storage is Microsoft's object storage solution for the cloud. Blob storage is optimized for storing massive amounts of unstructured data, such as text or binary data.
Blob storage is ideal for:
Serving images or documents directly to a browser.
Storing files for distributed access.
Streaming video and audio.
Storing data for backup and restore, disaster recovery, and archiving.
Storing data for analysis by an on-premises or Azure-hosted service.
Objects in Blob storage can be accessed from anywhere in the world via HTTP or HTTPS. Users or client applications can access blobs via URLs, the Azure Storage REST API, Azure PowerShell, Azure CLI, or an Azure Storage client library.
When you need to store relational data in a transactional manner with advanced querying capabilities, Azure SQL Database is the service for you whereas Azure Blob Storage can store non-relational data for you.