> Are the policies something like "retool" gets tokenized or faked data back, and the main app gets everything?
Yep, that's exactly right. Application credentials are grouped under classifications, and policies can be included/excluded across classifications. We aren't passing authz through JumpWire but for something like Retool you can configure it to connect through different proxies for different users.
> I prefer self-hosted and reasonably auditable code for such sensitive systems. Is that the case here?
Exactly. The engine which interacts with your data is almost always self-hosted, and the web app also can be if needed.
> At my scale (50 person company), it works reasonably well enough with just me maintaining it.
Makes sense! No reason to add more tools to your stack yet if the custom process isn't too burdensome.