A Generalized Serverless Event-Driven Architecture for Automated Receipt Processing and Data Extraction

Receipt volumes don't follow a schedule. Quiet for two days, then thirty submissions at once because someone's expense report is due. A server sitting on 24/7 for that is mostly wasted cost. The approach in this paper is based on serverless computing principles — resources remain inactive between executions. Upon data arrival, processing is triggered automatically, structured data is stored in a database system, users are notified. This represents the overall processing flow. The architecture consists of multiple functional layers. IPO notation tracks what enters and exits each stage — keeps the flow auditable without overcomplicating it. Paying per invocation beat committing to reserved instances; idle capacity between bursts doesn't bill, which is the whole point. Subtotal aggregation, tax application, and final transaction computation are all spelled out in the methodology. Full runtime benchmarking isn't something this paper gets into — that needs its own controlled test environment. This work focuses on the architectural design, while detailed implementation and performance evaluation are considered as part of future work.