A method for testing a server. A component (2) captures a session consisting of requests of and responses from a server (3). The captured session is stored as script files (4, 5). A GUI component (6) facilitates the identification of variable data (30) within the script files. Variable data is data which may vary from session to session. The identification process generates a database (14) with field headers (18) corresponding to the types of data identified (15). A component populates database (13). A driver component (9) uses the script files (11, 12) and the database (13) to test the server (3) by running multiple threads (10) each directing their own session with the server. Where data within the script files has been identified as variable data (13) the thread may substitute data from the database (13). A server testing apparatus and software for implementing the method is also disclosed.