When you create or update a product, creating all the necessary planning documents can seem like a useless paperwork exercise. Developing a project charter, work separation structure, and business requirements document may seem like wasted time. It follows then that not all documents are required for the new project. However, one of these documents certainly can point your team in the right direction and build a unified approach to work — this is the functional specification document (FSD).

There are many methodologies and standards for project management and project documentation that are used worldwide, such as Western standards “IEEE STD 830-1998”, “RUP”, “ISO/IEC/IEEE 2011″, ” Robertson and Robertson (2013)”. In this article we’ll not be tied to a specific approach and try to describe briefly the structure of the functional specification document (FSD) template and its most important sections necessary for filling.

At the end of this article, we will offer the template with the widest scope of detail, which you can download and use for different projects. At your request, you can exclude unnecessary sections from the template.

Download the Functional Specification Document (FSD) template

What Is a Functional Specification Document (FSD) Template or Functional Requirements Document (FRD) Template?

A functional specification document (FSD), also known as a functional requirements document (FRD), is considered by many project management and software development professionals to be a vital tool for streamlining chaos and misdirection in a project (in order to avoid the confusion between the concepts of FSD and FRD, in this article we will stick to FSD). Although FSDs are often associated with software and web development, they have an important role in any project, whether it is a new product launch, an update or software development, the creation of process, or organizational changes. Functional specification documents (FSD)s stand for both business and engineering expectations. All interested parties consider and approve this document. The result is a reference document for the proposed product addressed to all members of the organization, from coders to designers and sales staff.

You can adopt and use a functional specification document (FSD) template to ensure that you include all necessary development information in a document. In addition, the templates ensure that each new initiative of the team focuses on the product requirements rather than wasting time defining the design of the document specifications. Templates should be customized to meet the unique needs of each team or company.

Functional specification documents (FSD)s tend to be long, dry, and often technical. In addition, such documents may not be much needed and even useless. In the FSD document, covering all the details of the project may not be necessary. However, it is important to cover the key issues of the project for all stakeholders and avoid lengthy technical discussions. Although you can include many types of requirements and supporting information, it is recommended that your FSD should describe only the basic intent. Essentially, the FSD document must describe the context and specificity, and the functions that need to be developed. For example, a Technical Design document is created based on an accepted functional specification document. FSD must not duplicate any other requirements or documents included in the process.

Functional specification document requirements go through an approval process: business users verify that the solution resolves their problems, and technical reviewers verify that the described solution can be implemented. Often, key reviewers include testers, end users, technical writers, and product or system owners. You declare the document complete when everyone agrees with its content. Some organizations then form another architectural solution document.

A functional requirements specification document serves as a reference document for the entire team. It shows which products developers should develop, what testers should test, which writers should document, and what sales team should sell. Written functional specification documents (FSD)s show that the design and intent have been carefully considered prior to development. It also illustrates that after the specification clearance, all stakeholders arrive at agreement. Also, no specifications should be written and included in the document after the product has been coded.

Some business analysts and developers separate functional specifications from functional requirements, by saying that requirements describe what software should do and that specifications describe how software should do it. In practice, these two roles are often combined.

Functional specification document (FSD) templates can also take several descriptive forms. The chosen format depends on what works best for your teams.

Functional requirements: this is traditional for software and other technologies that use the waterfall development method. Functional requirements list characteristics and functions as what a product “should” do. For example, «the vacuum cleaner should trap particles smaller than five mm.”

Use cases: use cases often stand on their own. However, organizations that value user experience typically include use cases in functional requirements. Use cases set functions and properties in the context of user actions. For example, “the user double-taps the phone screen. The screen lights up. The user swipes the screen to the right to unlock the phone and its functionality.”

User stories: user stories are at the core of Agile development because they describe product design as something the user would be doing. This concise approach helps teams deliver benefits to users in the most effective way. User stories take the form of «as a user, I can do something to create some benefit.”

Who Uses Functional Specification Document (FSD) Templates?

Typically, business analysts and technical managers create functional specification templates that they share with business and technical stakeholders who evaluate them to ensure that the expected result meets the goal.

You can use functional specifications when developing new software and updates. You can also use them for organizational and system engineering changes, web development, and many other processes. The following user groups use the specifications:

  • Developers who code the product
  • Designers who create the user interface for a software, device, or website
  • Testers who ensure that the code works correctly and according to the specification
  • Marketers who prepare the documents that shape the demand around the new functionality
  • Sales teams that sell function and product
  • Technical support or user assistance professionals who document product performs for administrators, end users, and other roles

What Is the Difference between a Functional Specification Document (FSD) and a Business Requirements Document (BRD) ?

Although there are many combinations and variations of documents, functional specification documents (FSD)s and business Requirements documents (BRD)s sometimes differ.

BRDs describe the higher-level business requirements for a product (what a product does). BRDs avoid technical details in favor of a detailed rationale for the product. A clear understanding of what a product offers and why it is necessary can often help navigate product development through product direction disputes. FSDs can focus on describing the features and functionality of the product that are essential to achieve the end goal.

How Functional Requirement Document (FRD) Templates Relate to Other Specification Documents

Creating a product, whether tangible or operational, can involve creating many documents. The functional specification document (FSD) templates can be used in combination with any of the following options:

  • User Requirements: this document represents what the user expects from the product. Some consider the user requirements to be a part of the functional requirements document (FRD). If this document exists, it should be included in the overall development process. In Agile development, user requirements (expressed as user stories) are considered the core of functional requirements.
  • Product Requirements: used interchangeably with a market requirements document, this document details the purpose of the product.
  • Business Process Document: this document contains information about the business process.
  • Business Needs Assessment: this document describes the gaps between current conditions and desired business conditions.
  • Technical Design Specifications: the document describes (in the most accurate detail) the programming elements required for the proposed design.
  • Validation Documents: validation documents can include a traceability matrix which tracks features throughout the development process, test plans, and operational requirements. It is the process of demonstrating that a system or process meets a specific set of requirements.
  • Systems Requirements: this document outlines a high-level expectation for a system or product.
  • Business Requirements: the document describes the high-level reasons for making a product or upgrade.
  • Use Cases: this document offers functional information and context for functions from a user perspective.
  • User Stories: this document is used primarily for Agile development. It explains the intent of the product by detailing what the user will do with it.

What is the Difference between Functional and Nonfunctional Requirements?

Requirements can be classified as functional and nonfunctional specifications (the “how” and the “what”):

Functional Requirement: this is a description of the behavior, action, or expected outcome of a product or system. For example, “filter particles from water” or “print a page”. Common functional requirements include administration, authorization and authentication, audit tracking and reporting, and business rules. If the wording of the requirement answers the question “what should this do?” that requirement is functional.

Nonfunctional Requirement: Describes how something works, which also could be viewed as a constraint, attribute, or parameter. If the requirement statement answers the question “what should this have?” it is non-functional. Examples include usability, maintainability, and security, in addition to performance and regulatory requirements.

Functional Requirements Example

At a minimum, the functional requirements section should include the following information:

  • Who this product is intended for
  • Who is authorized to use the product
  • Input data into the system
  • What each screen should do
  • System workflows
  • Outputs
  • Regulatory requirements for the product
  • Specific business requirements of your company

How to Select or Create a Functional Specifications Document (FSD) Template

A written description of the desired features is an important part of product development, but what “works” in our teams should also determine the form that the functional requirements template takes. When developing a template, or even when considering improving an existing development process, ask anyone who is interested in the product development outcome what they want to see in the template. Each format has its advantages and disadvantages:

  • “Must” statements in traditional functional requirements tend to lack context and are more susceptible to interpretation by the developer.
  • Use Cases offer context and detail, but those very details can be critical — the real scale of the project becomes more apparent when user requirements become clearly defined. Obscure requirements can be lost among use cases.
  • User Stories provide descriptions of user needs in the context of business requirements. However, they may require additional effort (i.e. researching a suitable implementation). Developers and other users can also be so involved with individual stories that they sometimes exclude the broader context of the product

What to Include in a Functional Requirements Document (FRD) Template

While some requirements are basic, essential and communicate the purpose of your product, others may or may not be useful to the development of your product. The format you choose may also depend on what you are developing. Here is the most comprehensive list that you can use as a guide when preparing functional requirements:

  1. Introduction
    1. Instructions to authors
    2. Authors’ instructions
    3. History of changes
    4. Approval block
    5. Mailing list
  2. General description
    1. Terminology
    2. Document conventions
    3. Overall scope of the project and business process
    4. Overview of business requirements
    5. Description of the current system
    6. Proposed methods of solution
    7. Interaction between user roles
    8. Hypotheses, assumptions, dependencies
    9. Project boundary
    10. Links
  3. Functionality
    1. Functional requirements
    2. Use cases
    3. User stories
    4. Internal workflows of the system
    5. List of features or function descriptions
    6. Administrator’s functionality
    7. Error handling
    8. Product interaction with other products and components
  4. Data requirements
    1. Data model
    2. Data terms glossary
    3. Reports
    4. Receiving
    5. Integrity
    6. Data storage and disposal
  5. External interface requirements
    1. User interface
      1. Design prototypes
      2. Outlines or sketches
    2. Software interfaces
    3. Hardware interfaces
    4. Communicational interface
    5. Configuration management
  6. Platform and frameworks
  7. Testing and verification
  8. Benchmark for approval of work
  9. Setup
    1. Configuration
    2. Installation
  10. Attributes
    1. Portability
    2. Productivity
    3. Security
    4. Extensibility
    5. Internalization
    6. Support and maintenance
    7. User manual
    8. Reliability
    9. Availability
    10. User experience requirements

Functional Specifications Document (FSD) Templates for Agile Development

Agile focuses on finding the most efficient way to get a useful product to a user. In Agile development, writing traditional functional requirements in a document can sometimes be uneconomical. However, capturing more detailed plans and sketches can improve clarity.

One of the most common tools for describing Agile requirements is the user story. User stories provide features in the context of what the user needs to achieve. You can group similar user stories to form flexible epics. As with traditional functional requirements specifications, user stories describe a task or function, but not how the developers should implement it.

User stories use the following syntax: “as a user, I want to have something in order to obtain some benefit from it.” Here are some examples:

  • As a driver, I want to know when my battery needs replacing
  • As a cook, I want my tablet screen to be active while I’m completing a recipe;
  • As a cat, I want my portion of food in my bowl at 4pm every night.

To check if the user story is well written, rate it by using the following points –

  • Independent: Can the story be made independent of others?
  • Negotiable: Can I change or delete this story without affecting the rest of the project?
  • Valuable: Does this story have value for the end user?
  • Estimable: Can you estimate the size of the story?
  • Minimalistic: Is the user history small enough?
  • Testable: Can you check this story?

For project management purposes, you can assign a name and a numbered identifier to user stories in the tracker. In addition, you can mark the development priority, sprint and user story status. Stories are assigned to the Agile product Board (backlog).

User story templates are usually quite simple: they focus on defining the role of the user, template task, and what the task does.

Functional Specification Document (FSD) Template or Functional Requirements Document (FRD) Template

We now present to your attention our version of the most complete functional specification template. This generalized document includes all sections for maximum coverage of the description.

You can download the Functional Specification Document (FSD) template, remove redundant parts as needed and create the fully functional specification for your needs.