A step-by-step guide to building a real-time FAQ chatbot for a tax management SaaS using Gemini 2.5 Flash and NestJS. Covers setting up the Gemini SDK, understanding implicit vs explicit context caching, and streaming responses to clients using Server-Sent Events (SSE), async generators, RxJS observables, and NestJS controllers. Includes practical code for the chat service and controller, plus tips on meeting the minimum token threshold for implicit caching to activate.
Table of contents
PrerequisitesWhat Is Google Gemini?Understanding Context Caching in GeminiImplicit CachingExplicit CachingProject SetupBuilding the Chat ServiceSetting Up the ControllerTesting the ChatbotConclusionSort: