BSPOKE Software | Digital Transformation Partners

Software design documents: why should you write them?

Software design documents help a company to establish its goals for a product. Before starting your next project, you should take the time to work with your client, project manager, and colleagues to create software design documents. Some clients may think there’s no time for this, but we always recommend using these documents for any piece of work.

In fact, if someone shows no interest in writing software design documents, that may be the first red flag about working with them. Here we look at what software design documents are and how you benefit from using them.

What is a software design document?

Before getting started with your next project, you’ll want to put down your goals for it in a specification document. Your client may offer you theirs or you could write one for them to review. This will allow you to have goals that you all agree on, so there’s no confusion during the development process.

Software design documents don’t need to be excessively long and usually just offer a few detailed pages of information. This is one reason that companies often overlook this part of the process, as they believe it will waste time and resources they don’t have. By focusing on user interface and completion milestones, you can documents that will save you from disputes and communication troubles down the line.

A software design document gives you a clear reference point to refer to. When an issue arises, you’ll simply point to the document which the client signed off on. It’s important to note that the document can be adjusted at any point, but of course, this may come at an additional expense to the client if they add new requirements to their project.

Everyone wants to enjoy a good relationship with their clients and this is the first step to maintaining that. If you do find you have a client who refuses to take part in this process, think very long and hard about working together. You’ll have no back-up if difficulties arise.

What should be included?

To receive the benefits listed above, we always recommend including certain elements within a software design document. At a minimum, the project description, completion criteria, and milestones must be listed. You don’t need to go into details about how the project will be completed but focus on the expected end result. These are some of the key areas a good software design document will cover.

  • List of goals – Start with a paragraph stating your goals and the audience of your project
  • User interface – This is where the document will usually take the longest and involves a lot of back and forth between you and your client. Use a wireframe tool to showcase screen layouts, which will save you from future rewrites. Also, consider screen dimensions and graphic aspect ratios
  • Milestones – Your document should offer clear milestones which you and your client agree on. This can provide a rough estimation of completion and indicates component completion dates
  • Functionality – There are many key questions and concerns that must be answered in the document. You should indicate what the application does and at what speed. How failures are handled should also be discussed, as well as any limitations. Try to get as much detail as possible in this section, so you have no misunderstandings which result in rewriting code later on.

Keeping the document up to date

A good software design document will continue to evolve as your project does. There will always be issues or unexpected troubles that occur, and design changes are bound to happen throughout the process. As soon as a major change has been identified, ensure you update the document to reflect this. You should be in contact with your client each week, reporting on your work and checking that you are fulfilling their needs.

This will allow you to ask questions to identify any potential changes that are needed for the project. You’ll find the more regularly you discuss the project with the client, the sooner you’ll identify any concerns. If you leave this until the completion date, this can result in frustration and dissatisfaction from both sides.


There are many reasons to use software design documents in every project. Firstly, it’s a great exercise to establish the focus of the project. When so much discussion is occurring in the initial planning stages, it can be hard to know what the focus and aims of the project are.

You’ll have a clearer understanding of the client’s requirements and goals. This will get your team to buy into the project, so they’ll be supportive from the start. It will also give stakeholders a good idea of the benefits of the product and why they should support its creation.

Software design documents can help keep teams more focused and engaged inthe project, and they’ll have a clear goal in mind from start to finish. When you work on large projects and have no idea what the end goal is, teams can end up demotivated if troubles begin. Everyone will feel like they have a clear path for the journey, and designers and developers will be on the same page.

Where to from here

Software design documentation is something we recommend everyone using in any form of software development project. While you may think it’s a waste of time and energy at the start of the project, the money and resources you’ll save further down the line make its creation well worth it. Remember, you don’t need to overcomplicate the process, but by ensuring you and your client are on the same page, you’ll enjoy improved communication during your next project.

If you’re thinking about launching your own project, speak to BSPOKE Software.

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