> For the complete documentation index, see [llms.txt](https://docs.digit.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.digit.org/health/ph-v1.7/design/architecture/high-level-design.md).
# High Level Design
## **Overview**
The Health Campaign System provides:
* **Campaign Configuration**: Create and manage different health campaigns with specific attributes and goals.
* **Survey Management**: Define and assign surveys tailored to each campaign.
* **Progress Monitoring**: Enable real-time data collection and tracking via dashboards.
* **Integration Support**: Connects with other DIGIT modules (like Health Registry, Facility Registry) and third-party systems.
***
## **Architectural Design**
### Architecture Diagram
### Components Overview
| Component | Description |
| --------------------- | ----------------------------------------------------------------- |
| Campaign Service | Core backend service to manage campaign lifecycle |
| Survey Service | Enables survey creation, scheduling, and data collection |
| Notification Service | Supports citizen/staff outreach via SMS, IVR, or digital channels |
| Workflow Engine | Orchestrates the approval and campaign progression states |
| Analytics Module | Collects and visualizes campaign progress and outcomes |
| Registry Integrations | Interfaces with Facility, Staff, and Health registries |
| Mobile/Web Frontends | Interfaces for field workers, supervisors, and administrators |
***
## **Design Considerations**
* **Security**: Role-based access control for different user types (field staff, admin, supervisors). Data encryption in transit and at rest.
* **Scalability**: Built on DIGIT Core microservices, supporting large-scale deployments across districts/states.
* **Extensibility**: Config-driven campaign types, reusable workflows, and pluggable registries.
* **Offline Support**: Field apps support offline data collection and sync.
***
## **Data Design**
### High-Level Data Flow
1. Admin configures a campaign.
2. Surveys are created and assigned to health workers.
3. Data collected in the field is synced to the backend.
4. Dashboards and analytics display progress and coverage.
### Key Data Entities
| Entity | Description |
| --------- | -------------------------------------------- |
| Campaign | Metadata including type, target groups, area |
| Survey | Questions and structure tailored to campaign |
| Responses | Data collected from field execution |
| User | Health worker, supervisor, admin roles |
***
## **Technology Stack**
| Layer | Technology |
| ------------- | ------------------------------ |
| Frontend | React / Mobile App Framework |
| Backend | Java Spring Boot Microservices |
| Messaging | Apache Kafka |
| Workflow | DIGIT Workflow Engine |
| Database | PostgreSQL / ElasticSearch |
| Deployment | Docker, Kubernetes |
| Infra-as-Code | Terraform |
***
## **Deployment Architecture**
The solution is deployed using Kubernetes clusters managed via Helm and Terraform. It supports multi-environment setups (dev, staging, production). Key services are containerised, and CI/CD is managed via GitHub Actions.
***
## **Assumptions & Dependencies**
* Facility, Staff, and User registries are available and populated.
* Campaign types and workflows are pre-configured by the admin.
* Field devices have intermittent internet access to support data sync.
***
## **Risks & Mitigation**
| Risk | Impact | Mitigation |
| --------------------------------- | ----------------------------- | -------------------------------------------------- |
| Internet Unavailability in Fields | Delayed data sync | Offline data capture support |
| Workflow Misconfiguration | Blocked campaign progress | Pre-deployment validations and sandbox environment |
| Incomplete Registry Data | Inaccurate campaign targeting | Periodic registry audits and fallback mechanisms |
***
---
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