How to Write a Software Requirements Specification Doc


Remember the children’s game Broken Telephone or Chinese Whispers (transition chain experiment)? Players form a line, and the first person whispers a message to the second player in line. The statement goes down the line, and the last player announces it to the group. The goal is for the message to pass through the players without distortions or changes. It rarely happens that way, though. But for many, that’s the fun.

Embarking on a software development project without a software requirements specification document is like playing Broken Telephone. Except there’s nothing fun about it. Instead, you end up having frustrated team members, an ineffective product, or a failed project.

To avoid project delays and costly reworks, you need a document that describes the software development process. This way, project managers, software developers, user experience designers, and business analysts stay on the same page.

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What is a Software Requirements Specification (SRS) Document?

A software requirement specification (SRS) document is an overview of what your software product is supposed to do and how it should look. It defines the product’s goals, describes the design, and details the user and product requirements, including interactions with other software.

Let’s say you’re developing a gardening app that identifies flower and plant species, provides tips on plant care, and builds a community. Additionally, the navigation should be intuitive, the design minimalist, and it should work on the iOS and Android platforms. An SRS will ensure that the product the client wants is the one they get.

Features of a good SRS document must include:

  • Accuracy – Software requirements specification templates must reflect the product’s function and specifications as accurately as possible.
  • Completeness – SRS documents must contain all the features requested by the client with enough detail to complete the project.
  • Clarity – The template should be easy to understand to avoid misunderstandings or misinterpretations.
  • Consistency – The document should use the same format and terminology throughout.

This list is by no means exhaustive, but these points will ensure your SRS document looks professional and well-structured.

Why do you Need Software Requirement Specification (SRS) Documents?

It’s nearly impossible to develop software without an SRS. Think about it. How will engineers know which features to include? How will the testers know what to test? How will the UX designers know who the end-user is? How does the project manager compare the finished product with what the client asked for? 

Software requirement document templates eliminate confusion, delays, and cost overruns.

As a single source of truth that teams can refer to, everyone is clear on the product development specifications and deadlines. Additionally, SRS documents help project teams plan their work. 

For example, it provides coders insight on which programing language they’ll need and gives testers guidelines for designing test cases.

SRS documents are also communication tools between project partners. In the development process, changes are bound to occur. For instance, a design feature is added after feedback from users. Noting this addition in the SRS ensures all parties are aware of the change.

How to Write an SRS Document

Writing SRS documents is not easy. It must have all the information project teams need to complete the project. You are at a good starting point if you have software requirements specification templates. If not, don’t worry. There are many online tools to help you prepare software design document templates.

The basic framework of software requirements specification templates includes:

  • Introduction – defines the purpose, intended audience, and intended use.
  • General description – describes how the product works and users’ needs.
  • Requirements – explains the functional, non-functional, and system requirements

If you aren’t sure how to start, check out the software requirements specification template below for how to structure your document.

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Once you’ve established the outline, flesh out the SRS using the following six points.

  1. Outline the Purpose

This section of the document is a summary of the SRS. We believe it’s one of the most essential parts of the SRS document since it sets the tone for the project. Key components to include here are the project’s scope, intended audience and use, definitions, and references.

The project’s scope should describe the product in relation to business goals and objectives. This is critical for aligning project teams to a common goal. It also identifies activities, resources, timelines, and deliverables. 

Let’s say you’re building an online journal for a local writer’s association. The project scope may include automating article review and publishing processes, managing communication between authors, and a database of local writers and their work.

The intended audience refers to the people who have access to the SRS document. List all the relevant stakeholders and describe their roles and responsibilities in the project. 

For intended use, mention how the project team will use the document. For example, the project manager will use the SRS to estimate costs and project duration and identify potential risks.

Keep in mind that not everyone who reads the SRS document has technical knowledge. The product owner, for example, or sales teams who use the document’s information for sales pitches. 

Therefore, it’s necessary to include a glossary of terms, abbreviations, and acronyms. It allows anyone (regardless of their technical background) to understand the document. 

Also, add links to reference materials like articles, websites, or style guides that the SRS mentions.

Check this out…

example of software requirement specification

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The SRS sample above is for an online banking system. The introduction includes the purpose of the requirements document, the scope of the project, a table of terms and their definitions, and a list of references. 

Your SRS document should follow a similar framework.

  1. Identify the Target Audience

In addition to identifying the purpose of the SRS, you’ll need to pinpoint the document’s audience. 

As mentioned earlier, readers of SRS documents aren’t just project managers and software engineers. Different people will access the document. Think of investors, IT support staff who will maintain the software in the years to come, auditors, and other business function groups like marketing and sales teams. You should account for these audiences.

To identify the target audience, ask yourself who will use the document. The primary audience of software requirements specification templates is the project team – the software developers, designers, and testers. 

They use the SRS to understand the proposed product and the tasks associated with the requirements.

Other audiences are department managers who provide, review, and approve requirements. Marketing and sales staff use software requirements documents for product presentations and pitches and investors for making decisions on funding. 

Auditors will compare the product with the SRS document to ensure it meets all the requirements.

Once you’ve determined who will use the SRS and how they will use it, you will have a better idea of the type of information to include. 

For instance, sales teams have limited software development tools and processes knowledge. They will need detailed descriptions and diagrams of technical terms to understand the product and explain its benefits to users.

  1. Map the Need and Expectation

This step comes under the overall project description section in the software requirements specification template. Here you will inform the document’s readers about the product’s functionality. Specifically, you’ll describe the problem the product solves and identify potential users.

We recommend creating user personas to help you anticipate and map the user’s needs and expectations. User personas or profiles are data-driven, fictional representations of the target market. They provide a reference point to the project team members during the development and testing process.

Going back to our earlier example of the online journal, you’ll need user profiles for editors, authors, and journal readers.

You can also use map users’ needs with use cases. Use cases describe software requirements from the end user’s perspective. Take a look at this illustration:

Source

This use case diagram illustrates user interactions with an eCommerce website. Online shoppers place, cancel, and manage orders. 

Meanwhile, website administrators change order status and update products in addition to canceling and managing orders.

  1. Describe the To-Be-Built Product

You have already mentioned the proposed product in the introduction of the SRS template and will go into detail in the specifications section. So, what is needed here is an executive summary of the software and how it fits into the current tech network.

Explain if the software is new, a replacement, a stand-alone, or an add-on to an existing product. If the product is a stand-alone, explain how it integrates with other software and hardware. 

If it is part of another product, describe its interface to the existing operating environment. You should also discuss the environment in which the software will live, i.e., the operating system, hardware components, and other software.

Describe any issues that might constrain the development team, such as regulatory policies, hardware limitations, design standards, etc. List any user documents (tutorials, manuals) that accompany the software.

  1. Functional Requirements

Functional requirements are the features and functions the software product must have. As such, you need to provide developers with as much detail as possible. 

Rather than focusing on technical aspects, add use cases to describe how the user interacts with the product.

Let’s say you’re working on a document for a hotel booking site. The use case would include customers browsing dates and prices, selecting booking dates, and paying with a credit card. 

Some of the requirements from that scenario are a booking calendar with blackout dates, credit card collection, and customer data security.

External interface requirements are a type of functional requirement. They outline how the software interacts with other computing components. 

External interface requirements include user experience elements like screen layout and app navigation (user interface) and supported devices (hardware interface). 

They also include software integrations, like operating systems (software interface) and communication channels, such as emails or contact forms (communication interfaces).

Use requirements management tools to put together a list of requirements from all stakeholders, including customers. Customer surveys also provide valuable insight into which requirements to prioritize.

  1. Non-functional Requirements

Depending on your industry, you may need to include non-functional requirements in the SRS document. For instance, the aviation and medical device industries must track compliance regulations.

Non-functional requirements don’t affect the software’s functionality, but that doesn’t mean they aren’t important.

Functional requirements define what the product does, and nonfunctional requirements describe how it performs its function. 

For example, a functional requirement for an eCommerce shop might tell the website to send a confirmation email. The non-functional requirement could be to send the email within a minute of the purchase.

As such, nonfunctional requirements take into account the user’s experience and expectations. They cover security, usability, compatibility, scalability, availability, and performance requirements.

Don’t forget regulatory or environmental requirements if they apply.

SRS Document Examples

You can create software requirements templates in Google Docs or Microsoft Word. However, you will encounter change tracking and versioning problems.

Using requirements management tools like Tara AI to create your documents is the better option. There are key elements of an SRS document that you should note in order for your development team to deliver a product that aligns with the user needs. 

In your SRS document, start with detailing the objective. This is the business goals – where you state your mission and vision for the product and feature. 

After that, you explain how the project/product helps you attain your business objectives. Here is where you’ll describe the product and the problem it solves.

Then comes the user requirements section. Make sure to map user needs and expectations. You can use user stories, which describe software features from the customer’s perspective. 

Note: Don’t confuse user stories with use cases. User stories explain what software features look like to the end user, while use cases describe customers’ interactions with the software. 

The specifications section is where you provided a detailed list of all the specs. Be sure to include external interface requirements and non-functional requirements as well.

💡 Tips: make sure your points are clear, concise, and detailed in these documents. We also recommend documenting everything in your requirements documents, even questions or discussions, in order to provide more clarify around the feature or the product.

In Closing

Software requirements specification templates are critical for successful software development projects. Without them, your project will run longer than anticipated, cost more than budgeted, and produce a poor-quality product. You don’t want that.

Can you really entrust software requirements to verbal communications or emails? Preparing an SRS document may be an extra process in your workflow, but in the end, the efforts are well worth the trouble for a smooth-running project and high-quality product.

To that end, we shared six practices that ensure you create an effective software requirement document. They are: 

  • Outlining the document’s purpose
  • Understanding the target audience
  • Mapping out the needs and expectations the product will meet
  • Describing the product
  • Specifying functional and non-functional requirements. 

We also shared software requirements specification templates to guide you in building yours. 

More importantly, we showed you how to simplify and speed up the writing of SRS documents using the Tara AI requirements management tool. Get started with Tara for free today!