Billens

Billens is an HKI-certified web application that solves one of the most universally dreaded social experiences: splitting the bill after eating out with friends. The platform combines three core inventive systems into a seamless, end-to-end workflow. First, an Agentic Vision pipeline powered by Google Gemini 3 Flash extracts structured item data from receipt photos while handling edge cases like inclusive tax, free items, and handwritten notes. Second, a deterministic Proportional Math Engine distributes tax, service charges, and discounts to each person based on their exact consumption ratio, ensuring fairness down to the last rupiah. Third, an AI Action Processor translates natural language commands into precise application state mutations, allowing users to assign and adjust items through a conversational chatbot interface. Built on an Astro SSR/SSG hybrid architecture with React client-side interactivity and Zustand for state management, the application is deployed on Vercel with serverless API routes that securely proxy all AI interactions. The result is a tool that turns a 15-minute group argument into a minute automated process which transparent, accurate, and drama-free.