204No Content
The server has successfully fulfilled the request and that there is no additional content to send in the response payload body.
What this code obliges you to do
Do not retry automatically
Repeating the same request produces the same result. A retry loop here just multiplies load and hides the real fault.
Cacheable by default
RFC 9110 lists this code as heuristically cacheable, so a cache may store it even with no Cache-Control header. Send explicit headers if that is not what you want.
Must not send a body
This status must be sent with no body at all. Clients and proxies will mis-frame the next response on a connection if you send one.
When you see it
2Resource successfully deleted
Successful preflight CORS request
Effect on search
Neutral. Indicates no content is present, often used in API DELETE or PUT operations.
How to send it
1res.status(204).end();