According to one embodiment, a data sources interface of a mainframe receives a transaction request from a user terminal communicating through a network. The transaction request is formatted in a web-based format. A data sources function is called to instruct a mainframe application to perform the requested transaction, and the instruction to the mainframe is formatted in the native format of the mainframe. A transaction result formatted in the native format of the mainframe is received from the mainframe application. The transaction result is modified according to the web-based format to yield a data source, and the data source is sent to the user terminal.