Nova — An AI legal chatbot for Vietnamese securities

Overview

An AI chatbot platform for legal and financial information, specialised in the Vietnamese securities market. It applies GraphRAG on top of a knowledge graph to deliver high-accuracy answers. Built as multi-tenant SaaS, it aims at a template-based deployment model: customise, load the data, launch within two weeks.

Core technology

GraphRAG architecture

• Three-tier query generation: templates (80%) → DSL (15%) → Text2Cypher (5%)
• Nine-stage orchestration pipeline: circuit breaker with LLM fallback
• Hybrid retrieval: Neo4j graph database alongside pgvector vector search

AI safety

• Three layers against investment advice: explicit blocking → disclaimers on ambiguous phrasing → output filtering
• Hallucination detection: grounding scores, removal of false ticker matches, claim verification
• Cypher injection defence: graph query security on par with SQL injection protection

Data pipeline

News ingestion: CafeF/VnExpress RSS crawler → LLM extraction
Market data: 5-second polling → Redis streaming (during trading hours)
Celery Beat schedule: 6 automated jobs

Stack in detail

Infrastructure

Python 3.12 + FastAPI
Neo4j 5 Community (knowledge graph)
PostgreSQL 16 + pgvector (HNSW index)
Redis 7 + Celery (async jobs)
Docker Compose (7 containers)
Nginx 1.27 reverse proxy

AI/LLM

Claude Haiku — intent routing
Claude Sonnet — answer generation
multilingual-e5-large — multilingual embeddings

Security and compliance

Vietnamese PDPD compliance (automatic 90-day deletion)
PII masking (field removal + patterns + role-based + batch aggregation)
Redis sliding-window rate limiting
Audit logs and consent management

Scale

• 32 REST API endpoints
• 131 automated tests (31 seconds to run)
• 169 Python files
• 18 database tables
• Automatic language detection across Korean, Vietnamese and English

Multi-tenant management

• Tenant CRUD, onboarding, data upload and validation (8 endpoints)
• Workbench API: ontology, pipeline and metrics management
• Tenant isolation on a shared database

Current status

NOVA is in production validation across Vietnamese securities and legal domains. Because swapping the domain package carries the whole structure to another industry, we're extending it into internal policy search and customer-support assistants.

This is CoreCode's AI philosophy expressed as code — hallucination is engineered out rather than filtered after the fact, and no model answer reaches a user without clearing its grounding score.