Conversational Expense Tracking Using a Hybrid Language Model Pipeline
摘要
This paper presents a conversational expense tracking system accessible through WhatsApp messages. Users can log expenses or query spending habits using natural language, eliminating the need for specialized finance apps or spreadsheets. The system employs a hybrid LLM approach, routing simpler queries to a lightweight model for speed and cost efficiency, while complex inquiries are handled by a more capable model. Built with Flask, LangGraph, and Twilio, our system demonstrated faster response times than single-model alternatives without sacrificing accuracy. The method accommodates informal interaction in users’ current messaging practices instead of necessitating context switching to dedicated apps. Our results illustrate the strength of hybrid model routing in real-world AI applications, elucidating how smaller and larger models can cooperate to build scalable, inexpensive, and efficient solutions.