Cross-cutting Concepts

Domain Model

domain model

Authentication & Authorization

The platform uses a layered security approach:

  • Supabase Auth provides user registration, login (email/password, social providers), and JWT token issuance

  • Row-Level Security (RLS) in PostgreSQL enforces data isolation — users can only access their own data, agents can access their listings

  • Role-Based Access Control (RBAC) defines permissions for: Buyer, Seller, Renter, Agent, Developer, Admin

  • Workload Identity Federation secures CI/CD pipelines between GitHub/Azure DevOps and GCP without shared credentials

  • Account Federation between Google Workspace and Azure Entra enables single sign-on for internal team members

Location & Geocoding

Location handling is central to Asta Homes. The platform supports multiple addressing systems:

System Handling

Ghana Post Digital GPS

Addresses like "GA-543-0125" or "GA5430125" (without dashes) are both accepted. The system normalizes input and decodes to GPS coordinates.

Google Plus Codes

Open Location Codes (e.g., "9G5MGJ4G+X4") are decoded to latitude/longitude via the Google Maps API.

Traditional Addresses

Street addresses are geocoded via Google Maps Geocoding API with location autocomplete restricted to Ghana.

GPS Coordinates

Direct latitude/longitude input is supported for geofencing and property pinning.

Adaptive Image Quality

Property images are critical for the user experience. The platform implements:

  • Responsive image serving: Different image resolutions served based on device screen size and network conditions

  • CDN caching: Images are cached at Cloud CDN edge locations for fast global delivery

  • Format optimization: Modern formats (WebP, AVIF) served when supported by the browser

  • Lazy loading: Images below the fold are loaded on demand to improve initial page load time

Natural Language Search

The search system processes queries in natural English:

  1. Query parsing — Extract intent, constraints (distance, time, price), landmarks, and property types

  2. Entity resolution — Map landmark names to coordinates (e.g., "Kotoka airport" → lat/lng)

  3. Fuzzy matching — Handle spelling errors using edit distance algorithms

  4. Geospatial computation — Calculate distances/travel times using Google Maps Distance Matrix API

  5. Result ranking — Combine relevance, proximity, price match, and ML-based personalization

Machine Learning & Recommendations

  • Similar properties — Content-based filtering using property features (location, price, size, type)

  • User preference matching — Collaborative filtering based on browsing history and saved searches

  • Market predictions — Price trend analysis using historical transaction data

  • Search ranking — Personalized result ordering based on user behavior patterns

Workflow Automation

Windmill orchestrates the following key workflows:

  • Property listing approval — Automated checks + manual review for new listings

  • Saved search alerts — Periodic matching of new listings against saved search criteria

  • Transaction processing — Multi-step payment, verification, and notification flow

  • Data synchronization — Regular sync with Ghana Lands Commission and partner data sources

  • Report generation — Scheduled market analytics reports for agents and developers

Monitoring & Observability

  • Cloud Monitoring — Tracks request latency, error rates, container CPU/memory, and custom business metrics

  • Cloud Logging — Centralized structured logging from all Cloud Run services

  • Alerting — Automated alerts for SLA violations (targeting 99.999% uptime)

  • Dashboards — Real-time visibility into platform health, search performance, and user engagement

Internationalization

  • Default language: English

  • Multilingual support planned for: French, Twi, and other regional languages

  • Currency: Ghana Cedi (GHS) as primary, with USD and EUR conversion for international users

  • Date/time formatting respects user locale settings