Nailing Your Software Requirements Documentation | Lucidchart Blog
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Software development can be an exciting process of creative problem solving, design, and engineering. But underneath the shiny apps and polished web pages lies the less-sexy yet oh-so-important scaffolding that makes good software outcomes possible: documentation.

Documentation ensures teams and individual stakeholders are on the same page regarding a product or software application’s goals, scope, constraints, and functional requirements.

Unfortunately, the process of creating and documenting these requirements can be tedious, confusing, and messy.

Software requirements documents can quickly become long, unwieldy, text-heavy documents, making them especially vulnerable to errors, inconsistencies, and misinterpretations. Because of this, writing and using these documents can be time-consuming and lead to costly (and avoidable) design errors.

So what are product managers, software teams, and business leaders supposed to do?

While there is no one-size-fits-all rule for software development approaches, there are ways to reduce errors, save time, and drive effective results.

Below we walk through the goals and benefits of software requirements documents and a few best practices that will help you nail the process from start to finish.

software requirements documentation structure
Recommended Structure for SRD (Click on image to modify online)

What are software requirements documents?

A software requirements document (also called software requirements specifications) is a document or set of documentation that outlines the features and intended behavior of a software application.

In other words, the software requirements document (SRD) describes the business or organization’s understanding of the end user’s (typically the client’s) needs and dependencies as well as any constraints on the system.

What is included in an SRD?

While the SRD functions as a blueprint for managing the scope of a project, it ultimately only defines functional and nonfunctional requirements for a system. The document does not outline design or technology solutions. Those decisions are made later by the developers.

A well-written SRD should:

  • Break the problem into manageable parts.
  • Serve as a reference for testing and validation.
  • Inform the design specifications (i.e., the SRD needs to include sufficient information on the requirements of the software in order to render an effective design).
  • Provide feedback to the client (end user).

The SRD demonstrates to the client that your organization understands the issue they want to be solved and how to address those problems through software solutions. Because clients are often direct stakeholders, it is especially important to draft the documentation clearly in layman’s terms (avoiding technical jargon).

Again, how you write your SRD will depend on the approach and methodology your team or organization subscribes to. However, the IEEE standards organization recommends typical SRDs should cover the following topics:

  • Interfaces
  • Functional Capabilities
  • Performance Levels
  • Data Structures/Elements
  • Safety
  • Reliability
  • Security/Privacy
  • Quality
  • Constraints and Limitations

If each of these topics is clearly addressed and outlined in your documentation, you will have a more complete picture of the information necessary to develop your application.

How to nail your software requirements document

Whatever approach you take to documentation, follow these best practices to create an effective and efficient SRD.

Ensure requirements are complete

For a requirement to be “complete,” it should include all the necessary information to implement the requirement. This means when the designers and developers go to build out the function, they aren’t left making assumptions or guesses about the requirement.

For example, let’s say you’re developing a webpage. One of the requirements outlined is what should happen in case of an error. An incomplete requirement might say something like “In case of error, the system should exit smoothly.”

In this case, “smoothly” isn’t defined and is left up to interpretation. This ambiguity could lead to misinterpretation of the desired outcomes (and more work to go back and fix it).

To avoid this, write a complete requirement that defines what a successful function looks like:

“In case of error, the system must show an error page with the following message:

Uh-oh! It looks like something went wrong. Please try again in a few minutes. If the problem persists, contact our Support Team at support@website.com.

By defining a complete requirement, there is less ambiguity and a clear outcome for the development team to work on.

Make requirements testable

This is a fairly ubiquitous standard, yet too often organizations fail to write requirements that fully meet this rule.

Requirements need to be verifiable. Otherwise, there’s no objective way to know if the requirement was implemented satisfactorily.

For every requirement you write, make sure it is validated through one or more of the following ways:

  • Inspection
  • Demonstration
  • Walk-through
  • Testing

High-level requirements often undergo inspection or user testing, so they typically rely on more general specifications. But lower-level requirements that undergo software testing will likely need more detailed specifications.

Apply implementation-neutral functional requirements

As we noted earlier, an SRD is not a design document. It does not and should not define how the functional requirements must be implemented from a design standpoint.

Therefore, all functional requirements should be implementation-neutral. In other words, requirements should state what the system should do, but not how it should do it.

There are several advantages to implementation-neutral requirements, including:

  • A more efficient design process
  • Modifiable requirements that aren’t dependent on a specific implementation design
  • Less conflict between requirements resulting from opposing implementation details

Any constraints on implementation should be reserved for the non-functional requirements of the system.

Evaluate documentation with stakeholders

When all the software requirements have been documented, have all relevant stakeholders evaluate the final documentation before development begins.

Stakeholders should include designers and developers, testers who will validate the requirements, engineers, end-user representatives, and the client.

By having all stakeholders review and approve the documentation before beginning development, you improve satisfaction across the teams and increase the probability that the requirements will meet their needs.

Keep it organized

Finally, the name of the game is organization. To be effective, a software requirements document should be organized and clear. Many organizations rely on house templates to maintain consistency across projects. Templates are a great way to save time (just fill out the pre-organized sections) and stay consistent in your documentation process.

However, document templates often reinforce the problem of long-winded, text-heavy requirements. To avoid getting bogged down in pages of text, consider supplementing your documentation process with visual data.

Lucidchart documentation example
See how the Lucidchart team has used flowcharts for software documentation!

Lucidchart is a diagramming solution that helps software developers and their teams stay on the same page. Use Lucidchart to create flowcharts that efficiently and elegantly map out your software requirements specifications. Its features can help you:

  • Organize your requirements into a flowchart to keep your components distinct, your dependencies clear, and the stakeholders apparent.
  • Use swimlanes to visually describe which teams are responsible for each requirement set.
  • Quickly modify requirements or other data as the project needs evolve.
  • Link data (including additional documents) to support and inform your ongoing project.
  • Share the documentation (and any changes) instantaneously with relevant stakeholders.

Documentation doesn’t have to be a chore. With Lucidchart, easily document processes, user stories, and software requirements in one location. By visually defining your requirements specifications, you and your team will be able to find and act on information quickly while reducing opportunities for errors, inconsistencies, and misinterpretations.