A successful product begins with an insight — an idea about how to make users' lives better or how to solve an existing problem. But how do you ensure that the initial idea is implemented by the team exactly as intended? Requirements — sometimes called the runway for ideas — allow the entire team to reach a common understanding so the product can "take off."
What are Requirements?
Requirements (according to BABOK) are a useful representation of a need — a representation of goals, objectives, and outcomes that describe why a change was initiated and how success will be evaluated. In plain language, this is a way for non-technical people to express their ideas so that programmers understand them, and to reach a common agreement.
Roles in working with requirements:
| Role | Responsibility |
|---|---|
| Stakeholders | Voice their wishes about what the product should be |
| Business Analyst | Creates technical specifications, collects and traces requirements |
| Designer | Helps define the right UX/UI dimensions and aesthetics |
| Project Manager | Ensures the product is created on time |
| Development Team | Technically implements requirements |
| Product Manager | Responsible for the entire product from factory to installation |
Functional Requirements
Functional requirements describe the capabilities that the solution should have in terms of behavior and processed information. In other words, they define the main functions and capabilities of the product.
One of the most popular formats is User Stories, formulated as:
"As a [type of user], I want [functionality] in order to [achieve a specific goal]."
Example for a food ordering mobile application:
- As a user, I want to see a list of available dishes so I can choose what I like.
- As a user, I want to add dishes to the cart so I can place an order.
- As a user, I want to complete the checkout so I can receive food at home.
Non-Functional Requirements
Non-functional requirements define the quality characteristics of the system: performance, security, reliability.
Examples:
- System response time: Order processing time must not exceed 5 seconds under peak load of 1,000 requests per minute.
- Data security: All personal user data must be encrypted using the AES-256 algorithm, and data access is only possible after successful authentication.
Verification of non-functional requirements is often done with instrumental testing — for example, performance is checked using load tests, and security through penetration testing.
At What Development Stages Are Requirements Needed?
Requirements accompany the project at all stages of development:
- Gathering → formulation and clarification of requirements
- Analysis and development → functional requirements become the basis for design and programming; non-functional — a guide for quality assurance
- Testing → checking fulfillment of all requirements
- User acceptance testing → requirements serve as the basis for creating test scenarios
Requirements can go through a long journey: from the first meeting with the client to verification testing. The business analyst conducts interviews with stakeholders, transforms their ideas into specific requirements, documents them, coordinates with the development team, after which they become the foundation for designing and creating the system.
