This is a good practice tho. The HTTP code describes the status of the HTTP operation. Did the server handle it? No? Was the url not found? Did it time out? Was the payload too large? And the JSON describes the result of the backend operation. So 200 OK with error: true means that your HTTP request was all good, but the actual operation bugged out for whatever reason. If you try to indicate errors in the backend with a HTTP error code, you quickly get confused about which codes can happen for what reason.