Microsoft continues to expand the Azure ecosystem rapidly. One of the most recent delivered improvements was Azure SQL Database Serverless option. The new serverless model, which is currently in public preview, provides a compute tier for a single database that scales dynamically with the workload. This new compute tier is optimal for single database that have unpredictable usage patterns. Previously, you would provision the compute tier to your Azure SQL Database which allowed to have more granular control on scalability. The serverless tier scaling is effectively controlled by the service itself and will scale when needed.
This looks like it’d be good for a dev server, where the occasional startup cost is fine and there can be significant usage requirement differences based on time—after the devs go home, you’re not likely to need much compute.