The realisation of Service-Oriented Architecture (SOA) to communicate data between systems running on different platforms lack an organised framework to capture all the essential elements required for successful interoperability between web applications and their services. In this work, a SOA for Data Interoperability in Web Applications (SOADIWA) was designed to address this problem. The architecture of SOADIWA was based on five layers, namely Web Application Layer (WAL), Visualization Input Layer (VIL), Visualization Output Layer (VOL), Web Service Layer (WSL) and Quality of Service Assurance Certifier Layer (QoSACL). In WAL, the Service Provider (SP) received request from the Service Requester (SR) through the Stream Socket (SS) with a connection-oriented transmission control protocol that provided appropriate website for rendering of services. The SR provided requested data which must be accepted, processed and returned for a particular need using component object model and file transfer protocols. The VIL and VOL used Breshenham¿s line drawing algorithm and context-sensitive visualization techniques for data exploration and analysis.