Yes, it is possible to use Amazon Relational Database Service as a database hosting for FlexiCapture Database, since when using the MS SQL Server deployed at AWS RDS, you deal with SQL Server as it is. Also, AWS RDS allows you to use not only MS SQL but several different database engines (for example, Oracle Database or PostgreSQL).

If you use MS SQL Server or Oracle Database of supported versions hosted at AWS RDS, it is a legitimate and supported configuration for the FlexiCapture database server. However, please note that the platform may have its own limitations or special features that may make using it less comfortable or incompatible with desired configurations.