By default FortJs doesn't handle xml data in http body but can be configured very easily.

You need to create a class extending abstract class XmlParser

import { XmlParser} from "fortjs";

export class XmlToJsonParser extends XmlParser {

    async parse(xml) {
       // convert xml to string and return a json object    
    }

}

and pass this class in App configuration -

import { Fort } from 'fortjs';
import { XmlToJsonParser } from './xml-parser';

Fort.xmlParser = XmlToJsonParser;

You can take a look at example - xml-in-body.