Somebody really needs to write an open source Firebase clone. There's a gaping void in the market for something that doesn't lock users in and supports on-premise installs. This could be a pure open source project or open source business like MongoDB.

It doesn't need to be exactly Firebase. But Firebase sets a high bar. To my knowledge, there is no production-grade datastore that supports realtime sync, range queries, and eventual consistency in the face of intermittent connections.

Email tristan@sense.io if interested trial customer / sponsor.