In this paper we describe web-based distributed framework for building software systems to facilitate highquality teaching, learning and research of digital circuits design and test. Internet-based working becomes a necessity and a reality in modern society and the growing number of developed remote laboratories shows the perspectives of expanded use of the internet in learning process. On-line systems allow to use existing learning tools effectively by many users over the network organizing their experiments in a queue, storing the results for later downloading. The framework we describe has three-tier client server concept and supports massively parallel computing. There is one master server, several application servers and arbitrary number of users. Java applets are used as user interfaces. Coordinating Java servlet running on master server is responsible for communication support, task scheduling, task partitioning, user tracking, data management, etc. HTTP protocol based solution is used, since it is well established and flexible in firewall-protected environments. Reuse of existing CAD tools by encapsulation into Java agents extends the lifecycle and value of these tools.