System Design

Detailed system design documentation for HealthTalk.

Service Architecture

HealthTalk uses a microservices architecture with the following core services:

Message Service

Handles all messaging operations:

• Message composition and validation
• Template rendering
• Queue management
• Delivery tracking

Patient Service

Manages patient data:

• Patient profiles
• Communication preferences
• Consent management
• Contact information

Appointment Service

Scheduling and reminders:

• Calendar integration
• Reminder scheduling
• Confirmation handling
• Follow-up automation

Template Service

Message template management:

• Template CRUD operations
• Version control
• Approval workflow
• Variable substitution

Notification Service

Internal notifications:

• Staff alerts
• System notifications
• Webhook delivery
• Event broadcasting

Database Design

Primary Database (PostgreSQL)

Core relational data:

• Organizations and tenants
• Users and permissions
• Patients and contacts
• Messages and templates
• Audit logs

Cache Layer (Redis)

Performance optimization:

• Session data
• Rate limiting counters
• Template cache
• API response cache

Message Queue

Asynchronous processing:

• Message delivery queue
• Webhook delivery queue
• Notification queue
• Background job queue

Scalability

• Horizontal scaling via containerization
• Database read replicas
• CDN for static assets
• Auto-scaling based on load

Monitoring

• Application performance monitoring
• Error tracking and alerting
• Infrastructure monitoring
• Security event monitoring