3. Context and Scope
Business Context
System Context Diagram
External Interfaces
| Interface | Direction | Description | Protocol |
|---|---|---|---|
| Lender Platform API | Bidirectional | Submit valuation requests, receive completed appraisals | REST (JSON) |
| CoStar API | Inbound | Commercial property sales comparables, market metrics | REST (JSON) |
| FRED API | Inbound | Federal Reserve economic data (GDP, inflation, rates) | REST (JSON) |
| News APIs | Inbound | Current events and market sentiment signals | REST (JSON) |
| REIS API | Inbound | Market analytics and forecasting data | REST (JSON) |
| Authentication Provider | Bidirectional | User authentication and authorization | OAuth 2.0 / OIDC |
Technical Context
Data Flow
Technology Mapping
| Component | Technology | Rationale |
|---|---|---|
| Web Platform | React + TypeScript | Type safety, component reusability, investor-familiar stack |
| Backend API | Node.js + Express | JavaScript ecosystem consistency, async I/O for API aggregation |
| AI Agent (Smitty) | Python + LangChain | Rich ML/AI ecosystem, agent framework maturity |
| CRESI Calculator | Python + NumPy | Numerical computation efficiency, scientific library ecosystem |
| Memory Bank | PostgreSQL + TimescaleDB | Time-series optimization for historical outcomes, ACID compliance |
| Caching Layer | Redis | Sub-millisecond latency for frequent data lookups |
| Deployment | AWS (ECS Fargate) | Managed containers, auto-scaling, regulatory compliance certifications |
| Monitoring | Datadog | Application performance monitoring, distributed tracing |
Scope and Responsibilities
In Scope
CREstimate.ai Platform Responsibilities:
- ✅ Market sentiment analysis via Smitty AI agent
- ✅ CRESI 6-layer sentiment score calculation
- ✅ Integration with traditional appraisal methods
- ✅ Continuous learning from historical outcomes
- ✅ Explainable AI decision reporting for regulators
- ✅ API integration with lender platforms
- ✅ User authentication and authorization
- ✅ Audit trail and compliance reporting
Out of Scope
Not CREstimate.ai Responsibilities:
- ❌ Traditional appraisal data collection (property inspections, photos)
- ❌ Income/expense analysis (performed by existing appraisal software)
- ❌ Sales comparable selection (provided by CoStar, REIS, etc.)
- ❌ Final credit decisioning (lender responsibility)
- ❌ Regulatory filing submissions (lender responsibility)
- ❌ Property title research or legal due diligence
- ❌ Environmental site assessments
Rationale: CREstimate.ai augments existing appraisal workflows with AI-driven sentiment analysis, not replacing traditional methods or lender responsibilities.
For details on how these external systems are integrated, see Runtime View and Deployment View.