At a minimum, we need to store some things for the user study, but additional functionality (including user account info and personalization/customization options would be great).

I'd like this backend to be entirely cost and maintenance free, thus I am exploring platform-as-a-service options. Currently attempting to use google cloud storage free tier, but another (maybe better) option may be to use something like pouchdb and a free host like

• https://www.iriscouch.com/
• https://cloudant.com/

Amazon simpleDB is another alternative.

It is also possible to use things like google drive, google forms, or google fusion tables.

All user interaction with the "backend" desired:

private actions:

• user submits email
• user participates in study and data is submitted

public actions:

• user saves config/preferences
• user saves model or program state

The best plan at current seems to be:

• google forms submit data to spreadsheet for private actions
• public actions handled through google cloud storage or other free PaaS provider