A neglected serverless data store: Cloud Directory

I tried using this for a project a few months ago. On paper it sounds great, but I kept running into issues with their goofy schema system. It brought back bad memories of working with AD and LDAP. I ended up rolling my own (simpler) version with DynamoDB.

That said, it looks like they've somewhat addressed that problem with their automatic schema upgrades. If they were able to add Lambda integration I'd give it another look.