A Comprehensive Guide to Writing a Software Requirements Document for Companies and Start-ups

When embarking on a new software project, whether you’re a well-established company or a promising start-up, one of the critical steps in the development process is creating a software requirements document (SRD). 

An SRD serves as a blueprint for your software solution, outlining its features, functionalities, and the business objectives it aims to achieve. 

In this article, we will explore what a software requirements document is, its significance, and provide a step-by-step guide to help you craft an effective SRD that ensures the success of your software project.


What is a Software Requirements Document?

A software requirements document (SRD) is a comprehensive document that outlines the desired functionalities, features, and constraints of a software product or solution.

It acts as a formal agreement between stakeholders, including project managers, software developers, designers, and clients, to establish a clear understanding of the project’s scope, goals, and specifications.


The Significance of a Software Requirements Document

Clarity and Communication

An SRD helps in clearly defining and communicating the software project’s goals, features, and expectations to all stakeholders involved. It acts as a reference point throughout the development process, ensuring everyone is on the same page.

Scope Management

The SRD serves as a scope management tool, preventing scope creep by establishing boundaries and priorities for the development team. It helps in avoiding unnecessary feature additions and ensures that the project stays focused and on track.

Requirement Validation

By documenting the requirements, the SRD enables stakeholders to validate and refine their expectations. It allows for early identification of gaps, conflicts, or ambiguities in the initial requirements, minimizing costly rework and misunderstandings later in the development cycle.

Basis for Estimation

An SRD provides a foundation for estimating project timelines, resource allocation, and budgeting. It helps in breaking down the project into manageable tasks and determining the effort required to implement each requirement, facilitating effective project planning.

Future Reference

The SRD serves as a valuable reference document for future enhancements, maintenance, and system upgrades. It ensures that the original intent of the software solution remains intact even when modifications are made over time.

Risk Mitigation

An SRD is vital for mitigating project risks. By documenting requirements, dependencies, and constraints, it enables stakeholders to assess and address risks proactively. It provides a foundation for risk analysis and contingency planning, ensuring smoother project execution and minimizing the likelihood of setbacks or failures.


Writing a Software Requirements Document: A Step-by-Step Guide

Step 1: Define the Purpose and Scope

Clearly articulate the purpose and scope of the software project.

Identify the problem the software aims to solve, the target audience, and the expected outcomes.

Discuss the project’s objectives, constraints, and any specific business or technical requirements

A real-life example in case of a CRM Software Requirements Document:


The purpose of the custom CRM software is to streamline and enhance our company’s customer relationship management processes.

It should provide a centralized platform for managing customer interactions, tracking sales opportunities, and automating various tasks related to customer management.



The CRM software will include modules for contact management, lead and opportunity tracking, sales pipeline management, customer communication tracking, and reporting/analytics.

It will be accessible through both web and mobile interfaces, with integration capabilities with existing systems such as email clients and customer support software.

Step 2: Identify Stakeholders

Identify all the key stakeholders involved in the project, including clients, end-users, project managers, developers, designers, and quality assurance personnel.

Understand their roles, responsibilities, and expectations to ensure their needs are addressed in the SRD.



Company executives: They have overall responsibility for the success of the CRM implementation and will provide high-level strategic guidance.

Sales and Marketing teams: They will be the primary users of the CRM software, relying on it for lead management, opportunity tracking, and customer communication.

IT department: They will provide technical expertise, infrastructure support, and ensure data security and system integrations.

Customer Service team: They may need access to customer information and communication history for efficient issue resolution.

Customers: While not directly involved in the development process, their needs and expectations should be considered to ensure a user-friendly and effective CRM solution.

Step 3: Gather Requirements

Collaborate with stakeholders to gather requirements.

Use techniques such as interviews, surveys, workshops, and observations to elicit and document their needs.

Categorize requirements into functional requirements (features and capabilities) and non-functional requirements (performance, security, usability, etc.).



Contact Management: The CRM should allow users to create, store, and manage contact information, including names, addresses, emails, phone numbers, and relevant notes.

Lead and Opportunity Tracking: The software should provide functionality to track and manage leads from initial contact to conversion, including assigning leads to sales representatives, tracking communication history, and monitoring the status of opportunities.

Sales Pipeline Management: The CRM should enable users to visualize and manage the sales pipeline, track sales stages, and generate reports on pipeline performance.

Customer Communication Tracking: It should allow users to log and track all customer interactions, including emails, phone calls, meetings, and notes, ensuring a comprehensive view of customer history.

Reporting and Analytics: The CRM should provide built-in reporting and analytics capabilities, allowing users to generate performance reports, analyze sales trends, and identify areas for improvement.

Step 4: Prioritize Requirements

Prioritize requirements based on their importance and impact on the project’s success.

Use techniques like MoSCoW (Must have, Should have, Could have, Won’t have) or the Kano model to classify requirements into critical, high, medium, and low priorities.



Must Have: Contact management, lead and opportunity tracking, sales pipeline management.

Should Have: Customer communication tracking, reporting, and analytics.

Could Have: Integration with existing email clients and customer support software.

Won’t Have: Advanced AI-based features for now.

Step 5: Create Use Cases or User Stories

Translate requirements into use cases or user stories to depict how end-users will interact with the software.

Use narratives, diagrams, and flowcharts to describe the sequence of interactions and expected outcomes. This helps in visualizing the software’s behavior and validating requirements.


Use Case 1: Managing Contacts

  • As a sales representative, I want to be able to add, edit, and delete contacts.
  • I should be able to view contact details, including their communication history and notes.
  • I want to search for contacts based on specific criteria.
  • The system should provide a contact import/export feature.


Use Case 2: Lead and Opportunity Tracking

  • As a sales representative, I want to be able to create and update leads and opportunities.
  • I need to assign leads to specific team members and track their progress.
  • The system should provide reminders and notifications for follow-ups.
  • I want to generate reports on lead conversion rates and opportunity status.

Step 6: Define System Architecture

Describe the system architecture, including hardware and software components, databases, interfaces, and integrations.

Identify any existing systems or third-party software that the solution needs to interact with, and define the data flows between them.


The CRM software architecture will consist of:

  • Web-based front-end application developed using modern web technologies such as HTML, CSS, and JavaScript.
  • Backend server using a technology stack like Node.js and Express.js, providing APIs for data retrieval, storage, and manipulation.
  • Relational database management system (e.g., MySQL or PostgreSQL) for storing contact information, leads, opportunities, and communication history.
  • Integrations with existing email clients (e.g., Gmail) and customer support software (e.g., Zendesk) using their respective APIs.

Step 7: Document Functional and Non-Functional Requirements

Document the functional requirements in a structured manner, specifying each feature, input/output, and expected behavior.

For non-functional requirements, define performance targets, security measures, usability guidelines, and other quality attributes that the software must adhere to.


Functional Requirement

  • The CRM software should allow users to create, update, and delete contacts, leads, and opportunities.
  • It should provide search functionality to find contacts based on various criteria.
  • The system should generate automated reminders and notifications for follow-ups.


Non-Functional Requirement

  • Performance: The CRM should handle a minimum of 100 concurrent users without significant performance degradation.
  • Security: User authentication and authorization should be implemented to ensure data privacy and restrict access based on user roles.
  • Usability: The user interface should be intuitive, with clear navigation and responsive design to support both web and mobile access.

Step 8: Outline Assumptions and Constraints

Explicitly state any assumptions made during the requirements gathering process.

Identify and document any constraints, such as technical limitations, budgetary restrictions, or regulatory compliance requirements.



  • The CRM software will be developed using an agile methodology, allowing for iterative development and frequent stakeholder feedback.
  • The development team will have access to the necessary hardware and software infrastructure for testing and deployment.



  • The CRM software must be compatible with the existing company network infrastructure.
  • The budget and timeline for the project are limited, requiring a focus on essential features and efficient development.

Step 9: Include Acceptance Criteria

Define acceptance criteria for each requirement to establish measurable criteria for successful implementation. This ensures that the development team and stakeholders share a common understanding of when a requirement is considered complete and meets the desired outcome.


For the “Managing Contacts” use case:

  • Contacts can be successfully added, edited, or deleted without any errors.
  • Searching for contacts returns accurate results based on the specified criteria.
  • Contact import/export functionality works correctly without data loss or corruption.

Step 10: Review and Revise

Review the SRD with all stakeholders to validate the documented requirements and ensure that all concerns are addressed. Revise the document based on feedback and obtain formal approval or sign-off from all parties involved.

Writing a comprehensive and well-structured software requirements document is crucial for the success of any software project. It serves as a roadmap, aligning all stakeholders towards a shared vision and minimizing misinterpretations and rework. By following the step-by-step guide outlined in this article, companies and start-ups can create an effective SRD that lays the foundation for a successful software product or solution. Remember, investing time and effort in crafting a thorough SRD can save significant resources and ensure a smoother development process in the long run.

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