Jemboss is a graphical user interface (GUI) for the European Molecular Biology Open Software Suite (EMBOSS). It is being developed at the MRC UK HGMP-RC as part of the EMBOSS project. This paper explains the technical aspects of the Jemboss client-server design. The client-server model optionally allows that a Jemboss user have an account on the remote server. The Jemboss client is written in Java and is downloaded automatically to a users workstation via Java Web Start using the HTML protocol. The client then communicates with the remote server using SOAP (Simple Object Access Protocol). A Tomcat server listens on the remote machine and communicates the SOAP requests to a Jemboss server, again written in Java. This Java server interprets the client requests and executes them through Java Native Interface (JNI) code written in the C language. Another C program having setuid privilege, jembossctl, is called by the JNI code to perform the client requests under the users account on the server. The commands include execution of EMBOSS applications, file management and project management tasks. Jemboss allows the use of JSSE for encryption of communication between the client and server. The GUI parses the EMBOSS Ajax Command Definition language for form generation and maximum input flexibility. Jemboss interacts directly with the EMBOSS libraries to allow dynamic generation of application default settings.