Thanks for the quick response and this hint, will try it in a bit

which would allow you to have your RLS outside of a function (if that's important)

you still need a function, but that function will ONLY make a request and will always return false. Let's call it notify()

Then, in your RLS you can add a call to the function as a last argument of an OR clause. Assuming, PostgreSQL uses short-circuiting when evaluating RLS policies, your function will NEVER be called if the RLS check evaluates to TRUE

Here is an example

Let's say you have an RLS like this:

auth.uid() = some_user_id || notify()

if auth.uid() = some_user_id is TRUE AND RLS checks implement short-circuiting, notify() will NOT be called (since TRUE || FALSE is always TRUE)

if, on the other hand auth.uid() = some_user_id is FALSE, then the RLS check will invoke your notify function, which will send the request and still return false

I might consider it depending where I want my rls logic, I think it's better to have pseudo pure functions even in sql so your approach sounds really cool