I maintan a database of all markets on Manifold, for my search page. Right now I use the Manifold API, which is slow and buggy, resulting in out of date market info. It's possible to get the data directly from Supabase instead, which is much faster (though possibly just as buggy) but the Manifold admins have said that our access to that could be revoked at any time, or the output changed.
If I choose to move over and within the next three months after that there's any change to Supabase that causes me to have to spend more than half an hour fixing it, this resolves YES. Minor changes like a single property name changing that are trivial to fix don't count. Neither does something like a global outage that will fix itself later.
1,000The API is basically direct database access, so the main risks I see are of them turning bits of it off (or all of it off), or of database schema changing. The tables you're using about markets I think are pretty unlikely to change in a way that would break things, they seem pretty stable.
The main risk is that they turn the whole thing off or implement prohibitive rate limits. Turning the whole thing off means a replacement needs to be made for all the current API calls made by the web client, and this seems like a large amount of work unlikely to happen in any given 3 month period.
Rate limits in supabase are not an out of the box feature as far as I can tell, and require a bit of manual work, but can be done. And you might not be running afoul of them anyway (you'd hope not, since your app is a legitimate use case)
So I think this mostly comes down to "Will Manifold implement a replacement web client API in any given 3 month interval", and so isn't super likely, nor out of the question.