Is it possble to use Gamelift flexmatch with another cloud provider?

Amazon GameLift's FlexMatch service is designed to work directly with GameLift hosting. FlexMatch pairs up players and then hands the match information to GameLift, which proceeds to place the match in the best available hosting resources.

However, Amazon GameLift FlexMatch does offer some flexibility. You can use FlexMatch as a standalone matchmaking service. In this case, FlexMatch will form the matches and generate match tickets. It then becomes your responsibility to handle the match tickets, i.e., find suitable hosting resources (which can be servers outside of the GameLift ecosystem) and manage the player experience during gameplay.

So, while it's not directly integrated with other cloud providers or local servers, you can definitely make it work with some additional effort on your part. You would need to write some additional code to handle the handoff from FlexMatch to your local servers or another cloud provider.