What is a functional specification document?

Question

Accepted Answer

**Functional specification** — detailed description of system functionality.

**Contents:**
- System overview.
- Functional requirements.
- User interface.
- Data requirements.
- Business rules.
- Error handling.

**Example structure:**
```
1. Introduction
2. System Overview
3. Functional Requirements
   3.1 User Management
   3.2 Order Processing
   3.3 Reporting
4. User Interface
5. Data Requirements
6. Business Rules
7. Error Handling
```

**Difference from SRS:**
- **Functional spec** — what system does.
- **SRS** — includes non-functional too.

**BA role:** Create and maintain functional specification.

Business Analyst: What is a functional specification document?