Erbis stands with Ukraine

How to prepare a Software Requirement Document?

How to make Software Requirements Specification

Develop an effective SRS to make sure that all the stakeholders have a clear understanding of what needs to be built.

A Software Requirement Document (SRD) or Software Requirements Specification (SRS) is a document that outlines the specific functional and non-functional requirements of a software system. It's essentially a blueprint for the system, and it's vitally important that it's done well. The SRD is what the development team will use to build the system, so it needs to be accurate and comprehensive.

To create an effective SRD, you'll need to gather input from all the stakeholders, including the CEO, CTO, and developers. The document should be clear and concise, and it should outline all the requirements of the system, including its purpose, features, and design constraints.

There are many things to consider when preparing a software requirement document, but don't worry - we're here to help. In this post, we'll explain how to write requirements for software products.

System and infrastructure

Just as a house building starts with a foundation, a software project is based on IT infrastructure. 

IT infrastructure is a complex system that combines all hardware and software components for the smooth functioning of the software product.

The requirements for IT infrastructure depend on the business size and area.

For example, for large retailers, it is crucial to open new stores and warehouses and quickly integrate them into a corporate IT system. In this regard, the IT infrastructure of retail chains is characterized by effortless scalability, high performance, and uninterrupted system work.

In the banking sector, priorities are traditionally shifted towards security. Great importance is attached to the protection of financial and personal information. To ensure user data security, banks are increasingly partnering with cloud providers and renting secure server spaces on-demand.

No matter what kind of software business you start, you need to define the five major IT infrastructure components in your SRS:

  • Facilities: physical data centers and IT equipment

  • Network: routers, switches, firewalls, and load balancers

  • Storage: network-attached storage or storage area networks that enable data storage

  • Servers: physical and virtual servers

  • Infrastructure management tools: configuration, management, monitoring, and authentication tools

Components of IT infrastructure
Components of IT infrastructure

You will also need to determine the IT infrastructure requirements, which are also called non-functional requirements:

  • correctness

  • performance

  • reliability

  • robustness

  • scalability

  • security

  • usability

Non-functional requirement for software product
Non-functional requirement for software product

Additionally, you will need to define the type of IT infrastructure in your software product specification - on-premises or cloud. If you decide to develop in the cloud, you should also specify the cloud service provider of choice. 

Features and interface

This part of the SRS plays a crucial role for the CEO, CTO, product owner, and other product stakeholders. It describes how your system will function and look and how the user will interact with it.

Features and interface requirements are also called functional requirements. To outline functional requirements, you should understand what the user expects from the system. Remember, your goal is to write down the essential product features. You don't want to bog down the developers with superfluous details. Just focus on the basics and let them take it from there.

So, how to write features and interface requirements, and what to include in this part of an SRS? Here is a step-by-step guide:

1. Break down the functional requirements into user stories. These should describe different scenarios of interacting with your app from the user's perspective.

2. Define acceptance criteria. These should define clear requirements to consider a user story complete. In other words, you should provide a "definition of done" for each user story in your "to-do" list.

User story with acceptance criteria
User story with acceptance criteria

3. Create Work Breakdown Structure (WBS). Use a level system to break down development flow into tasks and subtasks. Then, gradually move from low-level to high-level tasks when implementing the project.

4. Prioritize software technical requirements. Assign each task a degree of importance using numbers from 1 to n.

5. Set deadlines. Define short-term and long-term goals of the development flow and document them in a product roadmap.

Roadmap for EHR software development
Roadmap for EHR software development

Third-party integrations

Third-party integrations significantly reduce development time and cost because you don't develop features from scratch but take ready-made services and integrate them into your app.

To make the process of external integrations smooth, you first need to decide which services you will utilize. The most common use cases of third-party integrations are:

  • Online payments. To enable online payments in your app you need to integrate a payment gateway, like Stripe or Braintree, and start accepting payments by credit/debit cards and virtual wallets.

  • Geolocation. If you need to track or place objects on a map, you can connect Google Maps or other GIS services to your software.

  • Communication chats. Instead of developing messaging programs, you can integrate Facebook Messenger, WhatsApp, Telegram, and other popular messaging platforms.

  • Analytics. Developing data analytics functionality can be a daunting task, however, you can significantly reduce your efforts by using ready-made services like, for example, Google Analytics.

  • Authorization. This may cover social login via Gmail, Facebook, Twitter, etc., or using a single sign-on feature for corporate software systems.

After listing appropriate services in your application development specifications, you will have to specify:

  • how the integrations are expected to work in your app

  • what value they bring to users

  • how you connect external services to your product

  • what APIs you are going to use

  • how you will handle security concerns

Example of documenting third party-integrations in SRD
Example of documenting third party-integrations in SRD

Software tools

During the development process, you will use a variety of software tools for development, testing, and deployment. Even though such tools are abundantly diverse, there are several categories to be distinguished in your software design specifications:

  • Development environments. This is software that provides all tools for faster and easier application development. Integrated development environments (IDE) can be language-specific or multi-functional and make it possible to work in different languages.

  • Version control systems. The purpose of such systems is to keep working versions of software and allow developers to roll back if the current version fails. The most used version control systems are Git, Subversion, and Mercurial.

  • Interface editors. The interface editor, also known as the GUI-constructor, can help you quickly create the program interface by dragging and dropping the necessary blocks.

  • Database editors. These editors help manage data sets and quickly organize data in a convenient format.

  • Programmer's tools for testing. There are many automated testing tools available today. The most popular are Katalon Studio, Selenium, Appium, and Eggplant. You need to select automatic testing tools for a specific task or write them by yourself.

  • Frameworks. These allow you to use ready-made modules when developing software and, thus, speed up the overall development process.

Software requirement specification example

An SRS is a document that describes the requirements for the development of a software product. Like any other document, it contains not only the main part, but also the introduction, definitions, intended use, intended audience, and other details.

Even though the content of an SRS is repeated across projects, there is no generally accepted form. Organizations decide how to document requirements on their own, and sometimes the lack of an SRD template can be confusing.

At Erbis, we have 10+ years of experience developing software projects, and we know how important it is to pay attention to planning. Before starting a project, our software engineering team conducts a discovery phase, draws up a product concept, and documents software requirements in an SRS document. Even though we use an individual approach to each software product, the requirements specifications template helps us organize data and present information to stakeholders in a well-organized way.

So, if you're looking for an SRS template for your project or just wondering what it looks like, feel free to download a full form using the link below.

SRS template


When it comes to developing SRS for SaaS or other software systems, it's important to remember that not all documents are created equal. While there are many different ways to go about crafting an SRS, following some simple guidelines can help you create a document that is both effective and helpful to your team.

Some key tips for creating an effective SRS include:

  • Defining your project scope and goals upfront

  • Listing all of the requirements (both functional and non-functional)

  • Breaking down each requirement into clear, concise steps

  • Ensuring that all stakeholders are consulted and approve the document

If you have a promising project idea but are not sure how to create software design specs, consider cooperating with a reliable outsourcing partner to help you develop an SRS and a system that fully complies with it.

October 23, 2022