AdTech, a fusion of technology and advertising, involves tools and strategies to enhance digital ad transactions, with programmatic advertising as a crucial aspect that automates and optimizes ad placements via data-driven mechanisms. Central to this is real-time bidding (RTB), where advertisers and Demand-Side Platforms (DSPs) engage in rapid auctions for ad impressions, necessitating advanced architecture for performance and scalability. The programmatic ecosystem consists of advertisers, publishers, Supply-Side Platforms (SSPs), ad exchanges, and Data Management Platforms (DMPs), all working together to ensure precise ad targeting and efficient transactions. The proposed reference architecture for a DSP emphasizes low latency, scalability, and efficient data integration, leveraging technologies like Aerospike for user data management and Redpanda for real-time data enrichment and analytics. This design enables DSPs to make instantaneous, informed bidding decisions, enhancing ad targeting and maximizing return on investment, while maintaining compatibility with existing RTB protocols.