POST responses should have a 429 too many requests HTTP status code, communicating a consumer has made too may requests
OpenAPI Response Post 429 Status Code Error
Message: POST Responses MUST Have 429 Status Codes
Policies
Response 4xx
Client error responses are where developer experience lives or dies. Consistent 400, 401, 403, 404, and 429 responses with shared schema references make error handling predictable.