I'm delighted to say we get a decent income from Patreon supporters and GitHub sponsors, as well as a little from commercial sponsors. It covers our running costs, and leaves some left over to save for contingency, and reward some contributors (myself included!).

I don't know what an Optiver salary would be (though I can guess: I work in finance too), but no, it's absolutely not a living wage :), lucky though I am to have anything for an Open Source project.

I do it as it's something I feel strongly about; it's got my name (and reputation!) staked on it (not as I'd planned it); and it's given me enormous opportunities too!