1. A method, implemented at a computer system that includes one or more processors, for brokering requests and data between a user and a content provider, the method comprising: receiving, at a middleware system, a request for data from a user, the request formatted in a first request format and requesting data from a content provider; translating the request to a second request format that is compatible with the content provider using configuration data, the configuration data comprising information used to transform data from the first request format to the second request format and information used to map custom messages in non-tabular formats from the content provider to uniform tabular format data or messaging formats; sending the translated request to the content provider; as a result of sending the translated request to the content provider, receiving a response from the content provider that comprises non-tabular, hierarchically-structured content; converting the hierarchically-structured content into tabular content, wherein converting comprises executing a series of xPath queries defined in the configuration data, including: performing one or more first xPath queries on the non-tabular hierarchically-structured content to identify repeating nodes previously defined in the configuration data in the hierarchically-structured content, and mapping the repeating nodes to rows in the tabular format; and performing one or more second xPath queries on the hierarchically-structured content to identify values for one or more elements or attributes previously defined in the configuration data and mapping the values to columns in the tabular format; and returning at least a portion of the tabular content to the user in response to the request for data from the user.