A 2xx means success to its requester. If you have an error in step 6 out of 13 that breaks the resource action, you shouldn’t be returning a success.
You might argue what to return and what kind of information to include in the response (like tracking numbers), but it shouldn’t be a 2xx and I don’t see how a misleading 200 would be more helpful than a 400 bad request.
I mean sure, in the strict meaning of the code-guides you are probably correct. Most problems stems for us at least from cross-reference issues which are normally configuration problems in the underlying system or other data-related issues. Those are often not neither the responsibility of the server or the client, and sometimes its both. There are often no code that is suitable to respond, and to just send “Bad request” when it’s a good request - does not make sense. Therefore i think it’s better to let badrequest be for bad requests, instead tell the client that sure, this is a good request but for this reason it didn’t work this time. This has to happen for it to work. Either i can do it with a simple structure in json with maybe 5 status codes and a message, or i have to figure out what 20 http status codes both i and the client has to implement and give them meaning that isn’t their intended meaning.
and to just send “Bad request” when it’s a good request - does not make sense
That’s when you use a 5xx status, then. The client doesn’t care how many other services you reach out to in order to fulfill their request. A 5xx code also covers failures in other parts of the system.
The customer expects a row to exist. The server does not find it.
The customer sent a valid request, and it should exist according to the customer.
The server could not find it. It can find others, but not that one, so from the server perspective it’s the client that gave the wrong id. If i always send a 404, the customer system think it did something wrong, which it didnt. Should they try to find the error on their side now, as it is a “client error”?
If i send a 500 every time, the customer will think the server is at fault, which it is. The server just could not find that row. What if the customer actually made an error, sending the wrong id, and i send the same code every time. It will be the servers fault every time the customer makes an error, and now they will never double check their inputs.
My point is, there is no nuance with these old codes. Obviously i will send a 500 for a caught exception and a 400 for a client error, but it is not always so easy.
