Most probably you have encounter the following error, while waiting response from other services(for instance it could be payment response from the integrator):

{
  "status": 415,
  "error": "Unsupported Media Type",
  "exception": "org.springframework.web.HttpMediaTypeNotSupportedException",
  "message": "Content type 'application/x-www-form-urlencoded;charset=UTF-8' not supported"
}

And most probably your endpoint is:

public class PaymentResponse {
    @PostMapping(value = ...)
    public String responseFromIntegrator(@RequestBody ResponseFromIntegrator reqBody) {
        // ...
    }
}

The problem is that when request’s media type is application/x-www-form-urlencoded, Spring boot doesn’t understand it as a RequestBody. To solve that problem we need to say to Spring Boot “accept the application/x-www-form-urlencoded request for the endpoint”

application/x-www-form-urlencoded request?

means that the HTTP POST request body is expected to be in the form URL-encoded format. In this format, the data is sent as key-value pairs, where the keys and values are URL-encoded. For example:

name=John+Doe&age=25&email=johndoe%40example.com

By setting the consumes field into the @PostMapping annotation right now spring boot accepts form-urlencoded request also: @PostMapping(consumes = {MediaType.APPLICATION_FORM_URLENCODED_VALUE})

By specifying consumes = {MediaType.APPLICATION_FORM_URLENCODED_VALUE} in the @PostMapping annotation, the method in the Spring Boot controller expects the request body to be form URL-encoded format.

But updating the annotation isn’t enough, we should also remove @RequestBody ResponseFromIntegrator reqBody because this has no relatioship with application/x-www-form-urlencoded request.

At the end our post request should be like this:

Spring Boot automatically converts the form URL-encoded data into the params parameter, which is a Map<String, String> containing the key-value pairs from the request body

public class PaymentResponse {
    @PostMapping( consumes = {MediaType.APPLICATION_FORM_URLENCODED_VALUE})
    public String responseFromIntegrator(HttpServletRequest httpServletRequest, @RequestParam Map<String, String> params) {
        String value = params.get("payment_field");
    }
}