Some quick replies: (I work at Inbox.) 1. Yes, we expose unread state via the tags endpoint. 2. Yes, check out the files endpoint 3. Currently we have filter

Some quick replies: (I work at Inbox.) 1. Yes, we expose unread state via the tags endpoint. 2. Yes, check out the files endpoint 3. Currently we have filtering on subject line, and we're working on full-text body search. (It's hard.) 4. Depends on the size of the emails. In general less than a minute. 5. Our OAuth flow is super quick. Access tokens are valid forever unless the user or developer revokes them. 6. Yes, see the `offset` and `limit` filter parameters, which let you page nearly any API query.