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b5b2e4 Melisha Dsouza 2026-04-09 07:50:00 1 
# **Low-Level Design (LLD) Template**
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ab13bb Melisha Dsouza 2026-04-09 07:56:46 3
**Document Revision History**
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| Ver No | Date | Change Information | Author | Approver |
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|--------|------|--------------------|--------|----------|
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| V1.0 | Date | Initial Draft | Author Name | Approver Name |
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b5b2e4 Melisha Dsouza 2026-04-09 07:50:00 10
### **1. Problem Statement**
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- Clearly describe the problem in 2–3 lines
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- Mention what needs to be achieved and why
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**Example:**
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Admin dashboard should display the count of pending transfers so that operations team can monitor incomplete transactions and take timely action.
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### **2. Scope**
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- What is included
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- What is excluded (if any)
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### **3. Solution Approach (Technical Design)**
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#### **3.1 Overview**
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- High-level explanation of the solution
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- **Mention whether:**
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- Existing services will be reused
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- New services/APIs will be created
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- Existing services will be enhanced
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#### **3.2 Components / Modules Involved**
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- **List all impacted modules:**
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- Backend services
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- Frontend/UI
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- Database
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- External integrations (if any)
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#### **3.3 API Design**
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- **For each API:**
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- **API Name:**
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- **Method**: (GET/POST/PUT/DELETE)
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- **Endpoint:**
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- **Request**:
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- **Response**:
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- **Auth Required:** Yes/No
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- **Service Handling It:**
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#### **3.4 Data Flow**
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- Step-by-step flow of how data moves across systems
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- **Mention**:
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- Source of data
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- Processing logic
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- Final output
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#### **3.5 Database Impact**
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- New tables (if any)
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- Changes in existing tables
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- New fields/columns
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- Indexing (if needed)
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- Query changes
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#### **3.6 Business Logic**
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- Core logic/conditions
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- Rules to calculate/derive values
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**Example:**
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Pending transfer = transactions where status IN (initiated, processing, on-hold)
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#### **3.7 Service Design**
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- Number of services impacted/added
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- **Description of each:**
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- New service
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- Modified service
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- Reusable service
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#### **3.8 Error Handling**
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- Failure scenarios
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- Retry mechanisms
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- Logging strategy
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- User-facing error messages
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#### **3.9 Edge Cases**
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- List all possible edge cases
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**Example:**
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- Transfer stuck due to insufficient liquidity
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- Partial transaction completion
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- Duplicate requests
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#### **3.10 Performance Considerations**
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- Query optimization
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- Caching (if required)
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- Pagination / batching
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- Expected load
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#### **3.11 Security Considerations**
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- Authentication / Authorization
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- Data masking (if applicable)
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- Sensitive data handling
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### **4. Sequence Diagram**
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- Visual flow of request → processing → response
ab13bb Melisha Dsouza 2026-04-09 07:56:46 103
- **Must include:**
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- UI
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- Backend service(s)
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- DB
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- External systems (if any)
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### **5. Unit Test Criteria**
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- Define test scenarios:
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**Example:**
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- Valid pending transfers count
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- No data scenario
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- Error response handling
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- Edge case validation
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### **6. Integration / QA Test Scenarios**
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- End-to-end scenarios
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- APIUI validation
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### **7. Dependencies**
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- External services
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- Other modules
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- Data availability
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### **8. Assumptions**
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- Any assumptions made during design
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### **9. Risks & Mitigation**
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- Potential risks
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- How to handle them
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### **10. Deployment / Rollout Plan**
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- Any migration required
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- Backward compatibility
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- Feature flag (if needed)
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### **11. Open Questions**
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- Any pending clarifications