Functional Specification


Functional specification is a detailed document that outlines the expected behavior of a certain system or software. It describes the features and functionalities that the system or software should possess and how it should react to specific inputs. The document serves as a guide for developers during the development phase and provides a clear understanding of what needs to be created and its intended purpose.


The phonetics for “Functional Specification” is /ˌfʌŋkʃənəl/ /ˌspɛsɪfɪˈkeɪʃən/.

Key Takeaways

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  1. Functional Specification is a detailed description – It provides an exhaustive elaboration of a software system’s functionalities, interactions and dependencies, providing a clear guide for developers before the design phase.
  2. It serves as a blueprint for development – The specification acts as a roadmap for the system’s development process, outlining the system’s capabilities, appearance, and interactions, which help the development team foresee and handle complexities.
  3. It plays a critical role in project management – A functional specification assists in organizing assignments, managing resources, and timelines in a project. It helps in reducing project risks and cost overruns and plays a fundamental part in ensuring successful project execution.

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    Functional Specification is a crucial technology term because it serves as a comprehensive blueprint for the behavior of a system or software product. This detailed document defines what the system or software will do, its interactions, operational requirements, and user interactions, which are fundamental in the development process. It allows developers, project managers, and users to align their understanding and expectations, thus reducing confusion and miscommunication. Therefore, Functional Specification plays an important role in providing direction for software development, ensuring that the final product meets the users’ needs and requirements, resulting in a successful project outcome.


    A functional specification, often referred to as a functional spec, serves as a blueprint for how software or a system needs to function to successfully achieve a set of goals. It is a formal document that explains in detail the capabilities that a certain system or application will have. By defining what the system or software should do, it gives developers a clear understanding of what needs to be created and provides a means with which they can effectively design and build a system or software that meets the stated requirements. The purpose behind a functional specification is to clearly communicate the expected behavior of the system/application to various stakeholders including designers, developers, project managers, and testers. It provides a detailed understanding of workflows, system behaviors, and all the technical requirements. In practice, it is used for developing test cases and arriving at cost, time, and resource estimates. It empowers developers and designers to create an effective solution which aligns with the user needs while aiding in creating a shared understanding and agreement over what the final system will do.


    1. Mobile Application: When a company wants to develop a new mobile application, they would need to have a functional specification. This can include detail about user interface design, database management, security features, notification services, integration with other applications, user login and authentication, and various functionalities of the application like posting content, making purchases or chatting with other users.2. E-commerce Website: For an e-commerce website, a functional specification could outline the process for product searches, product categorization, customer reviews, shopping cart management, payment gateways, shipping methods, inventory management, and customer service features.3. Automobile Manufacturing: In the automobile industry, a functional specification for a new vehicle model might include details about the car’s engine specifications, fuel efficiency, seating capacity, interior and exterior features, safety systems, entertainment systems, etc.

    Frequently Asked Questions(FAQ)

    Q: What is a Functional Specification?A: A functional specification is a formal document used to describe in detail for software developers a product’s intended capabilities, appearance, and interactions with users. Q: Why is a Functional Specification important?A: Functional specifications align everyone on the team to understand exactly what is to be built. It removes ambiguity and potential misunderstandings, helping to manage project scope and avoiding added costs or time delays.Q: What information does a Functional Specification generally include?A: A functional specification typically includes details about the data input and output, user interface, user interaction, and system behavior or functionality. It may also include diagrams and mock-ups showing how the software works.Q: Who creates a Functional Specification?A: In most cases, a Business Analyst, Systems Analyst, or a Project Manager who understands the users’ needs and the system capabilities will create the functional specification.Q: Do all projects need a Functional Specification?A: Although this largely depends on the scale, complexity, methodology, and nature of the project, it’s generally recommended to have a functional specification for most software development projects. Q: When is the best time to produce a Functional Specification?A: The Functional Specification should be produced after the requirements are gathered and before the development begins.Q: Can a Functional Specification change over time?A: Yes, it can change over time due to changes in business requirements, customer needs, or project objectives. Changes should be documented properly to keep everyone aligned.Q: What is the difference between a Functional Specification and a Technical Specification?A: A Functional Specification describes what the system should do from the user’s perspective while the Technical Specification outlines how the system will accomplish these requirements, like what technologies, architecture and techniques will be used.

    Related Finance Terms

    • Software Requirements
    • Product Development
    • User Stories
    • Process Flow Diagrams
    • Technical Specifications

    Sources for More Information


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