Apache Hadoop and Apache Spark are two powerful open-source frameworks designed for handling and analyzing vast volumes of data. While they share similarities as distributed systems, their architectural differences, performance characteristics, security features, data processing capabilities, and cost implications make them distinct choices for big data analytics. Spark excels in real-time stream data analysis, machine learning applications, interactive data exploration, fraud detection & anomaly identification, and personalized recommendations due to its speed and in-memory computing power. Hadoop, on the other hand, shines with its scalability and cost-effectiveness in handling large datasets, data warehousing & data lakes, log analysis & extract-transform-load (ETL), big data on a budget, and scientific data analysis. The optimal choice between Spark and Hadoop depends on specific business needs and priorities, such as identifying data processing needs, evaluating existing infrastructure and compatibility, integrating capabilities with other big data tools, and aligning with long-term project goals and scaling needs.