HTTP API Interface for data reading and writing.
This is completely outside the scope of our current project. The current project aims at a desktop application, potentially with multi-user capabilities, but in that case the database is the server, not gnucash. Sorry for that.
Stuart King commented
An API would be really great, I understand the issue to a degree, but could the two ideas not be kept together? Having an API to allow posting of transactions into and retrieving transactions from the database, which could be on a server though not necessarily. I would love to have the ability to post transactions into an accounting system even on a desktop ;) from another application, this is a requirement we have right now.
Anyway, I respect your decision, but I do think we could develop in a way that both models worked.
Hideaki Shiina commented
GnuCash as a server.
It brings easy customizable client and flexibility of applying new technologies.