online personal finance software that I can host myself
I generally concur with your sentiments. mint.com has 'hack me' written all over it.  I know of two major open source tools for accounting: GNUCash and LedgerSMB. I use GNUCash, which comes close to meeting your needs: The 2.4 series introduced SQL DB support; mysql, postgres and sqlite are all supported. I migrated to sqlite to see how the schema looked and ran, the conclusion was that it runs fine but writing direct sql queries is probably beyond me. I may move it to postgres in the future, just so I can write some decent reports. Note that while it uses HTML for reporting, there is no no web frontend. It still requires a client, and is not multi-user safe. But it's probably about the closest to what you what that still falls under the heading of 'personal finance'. A fork of SQL Ledger, this is postgreSQL only but does have a web frontend. All the open source finance webapps I've found are designed for small to medium busineses. I believe it should meet your needs, though I've never used it. It might be overkill and difficult to use for your limited purposes though. I know one or two people in the regional LUG use LedgerSMB, but I really don't need invoicing and paystubs.