Back-end as a service (aka BAAS) tools for front-end developers

Data/back-end management as a service:

• Back& [free to $]
• Firebase [free to $]
• Kinvey [free'ish to $]
• Parse [free to $]
• Pusher [free to $]

User Management as a Service:

• Auth0 [$]
• Hull [$]
• UserApp [free to $]