Quick... everyone run to www.graph.cool !! It's parse but for GraphQL!
In general GraphQL provides many advantages over a traditional REST like API provided by most BaaS. It frees you from the need for proprietary SDKs and reduces vendor lock-in.
Here is a quick way how you can get started: https://www.graph.cool/docs/quickstart
They offer a interesting product but i think at this moment it has the exact same problem that Parse had (my other comment in this thread), you don't have access to the raw data, hope they will do that in the future (provide direct access to the source database), it will certainly be a more interesting/flexible service
I'd be very keen on hearing your experience getting started building something on Graphcool!