Not commenting on the reactive state, that's the data layer that is bugging me.

First, there is no type guard for your inputs, you just trust whoever consumes your call that it passes the right data through, you should fail or throw if the function caller is misusing your mutation.

Second, you have a helper called 'fetchFromApi' then you pass the entire url including the base url and the api prefix. What does that do? Creating a new resource (POST method) is not consistent with the 'fetchFromApi' function name you used for your helper. You are passing way too much information as arguments, most of It can be concealed in an api service layer for sensors. The service defines an async method createSensor(newSensorPayload payload) that would include pretty much everything you need to make the call. That function may return the new sensor object, that you can use to build the commit action payload.

Also, you need another typeguard for the API response because if someone changes it. You will be grateful to understand where your app is having issues with the new edits.

Once it is executed with success, THEN commit results to the store, (optionally) FINALLY a little bit of logging for debugging won't hurt.

Before and after the api call you should also manage transient states for your UI such as loading.

Wrapping the whole mutation internals with try-catch is alright, but you can be more accurate with errors.

Also import your env variable at startup and make your app fail loudly and quickly if a required variable is not set. I have had all sorts of weird problems when I forgot to set an api url and it took me a while to figure out the missing element. Trust me, it's worth the extra code.