How to Write a System Requirements Specification (SRS)

Structure, write, and review an SRS that all stakeholders can rely on.

This guide walks through producing an SRS document that defines what software must do and how it must perform, and that all stakeholders can agree on before development begins.

1. Understand the purpose of an SRS

An SRS defines what the software must do and how it must perform. It creates a shared understanding between customers, developers, engineers, and project managers by documenting behaviors, functions, performance expectations, and constraints. It includes functional and non-functional requirements, but excludes design decisions and information not explicitly required by the customer.

Once approved, the SRS becomes a formal agreement guiding development, validation, and future reference — acting as an "insurance policy" that resolves scope uncertainties by referring back to the document.

2. Know why you're writing one

3. Draft the document in three parts

Before writing, make sure you can answer: What should the software do? How should it behave? What are the performance expectations? Are there constraints?

  1. Introduction — Define the purpose of the software, what it must and must not do, the core problems it solves, who the intended users are, and optionally a high-level overview of the document's structure.
  2. General Description — Describe the system's overall functionality and environment: user expectations, required hardware, and all relevant interfaces (system, user, hardware, software). Document important assumptions or dependencies.
  3. Specific Requirements — Break the system into precise inputs, outputs, processes, performance criteria, and integration details. Define both functional and non-functional attributes, including usability, security, availability, and maintainability.

With this outline in place, collaborate with the client to fill in every detail. Get the final version reviewed and approved by all key stakeholders before development begins.

4. Avoid common mistakes

5. Consider a requirements management tool

Requirements management platforms (such as Jama Connect) can simplify SRS creation by tracking decisions, relationships, dependencies, and regulatory requirements throughout the development lifecycle. When selecting a tool, look for:

CapabilityWhat it gives you
ConfidenceClear traceability that highlights potential risk areas.
VisibilityInsight into relationships across teams, systems, activities, and results.
SpeedFaster alignment and reduced rework through structured tracking.
AdaptabilitySupport for your organization's workflows and processes.
Performance MonitoringAbility to track team performance and measure process improvements.
A good requirements management solution gives your team the ability to analyze impacts, maintain traceability, streamline collaboration, and deliver a high-quality product that meets customer expectations.