Mortgage assistant: how a message is handled

Mortgage assistant: how a message is handled An architecture diagram generated by Archify. Website chat · Customer types in English · Architecture component Website chat Customer types in English PII guard · Local detector, fails closed · Architecture component PII guard Local detector, fails closed FastAPI + LangGraph · Routes, validates, commits · Architecture component FastAPI + LangGraph Routes, validates, commits LLM: GPT-4.1 or local Qwen · Picks IDs only, never free text · Architecture component LLM: GPT-4.1 or local Qwen Picks IDs only, never free text Session RAM facts · Amounts stay on the server · Architecture component Session RAM facts Amounts stay on the server Python tools · Decimal LTV + Refinance draft · Architecture component Python tools Decimal LTV + Refinance draft Start application · Prefilled, editable form · Architecture component Start application Prefilled, editable form Retrieval + rerank · BGE-M3 x2, reranker, 0.23 gate · Architecture component Retrieval + rerank BGE-M3 x2, reranker, 0.23 gate 1,476 reviewed records · English PDFs, Swedish sources · Architecture component 1,476 reviewed records English PDFs, Swedish sources message safe turn safe candidates LTV / draft draft commit facts public question frozen index Legend Frontend Backend Database Security