Technical specification for software development

In short, it provides you with an opportunity to fulfill your end desires. Notably, it is a critical stage to do before you start your development progress, especially when developing a web or mobile project. Without it, most developers cannot get a clear picture and determine the single definition of what the project they are yet to create should look like from the perspective of programming.

Other significant advantages include the following. Read more about the purpose of technical specification in our article. While there are many approaches to writing per se, the technical specification requires, well, technical writing skills and wording.

It should deal with concrete terms that are unanimously understood and therefore avoid creating confusion. The steps below outline the procedure to follow and significant parts of how to write a technical specification document. The first phase is an evaluation of whether the specification to be written will be a closed one or an open one. An open spec leaves freedom to the entire entity that establishes a product to fulfill the specification.

A closed spec designates tools and other requirements as well as other performances that must be utilized in the product design to meet specifications. The second phase is to determine the requirements.

Creating a table of contents should form the last task. Part two of the process involves creating the actual specification. Other factors include the environment, tolerances, details to achieve, and the project's expected lifespan. Lastly, part three of the TS is the completion of the document, which involves assigning a title as well as a control number having revision ability on the spec.

The signature block should be included, both generating authority and authority in charge of making changes in the document. The final reading on the project should be then made and any loopholes sealed. Writing a TS document is a crucial prerequisite to a successful project.

Therefore, the outlined details must be observed such as a table of contents, the definition of terms, use of precise and straightforward language, and signature block. While an important function of a software design doc is to communicate the technical details of the planned solution to your team, it's not the only reason why it's written.

The objective is no longer to create a detailed, fixed blueprint for your design and serve as documentation later on. It's to help you organize your thoughts before wasting a bunch of time implementing the wrong solution or the solution to the wrong problem. It's a collaborative exercise for your entire team. If you are working as a freelance developer, a design document can also save you a lot of trouble down the road by helping you avoid potential disagreements with your clients and adding clarity to the agreed-upon goals.

A software design document describes the solution to a problem. So naturally, since every problem is different, there can be no one-fits-all template. No two software design documents are alike. Here's what a software design document could look like in Nuclino. Nuclino is a unified workspace where you can not only collaborate on design documents, but also build your internal knowledge base , collaborate on internal documentation , plan sprints , onboard new employees , take meeting minutes , communicate asynchronously , and bring all your team's work together in one place.

While your project may require a custom design document structure, you might want to consider including some of the following commonly used sections:. The title of your design document and the list of people planning to work on the project. A high-level summary that every engineer at the company should be able to understand. An explanation of why this project is necessary and how it fits into the overall strategy. A description of the expected impact and the metrics that will be used to measure success.

Of course, there is no such thing as a definitive design document template. Many alternatives have been proposed, some simpler, some more detailed. The choice would strongly depend on the scope of the project and the size of your team.

However you decide to structure your SDD, the important thing is to find the format that works for you and your team and continuously iterate on it.

The style of writing a software design document is purely subjective and usually a matter of personal preference. Again, you can take a look at our full guide to non-functional requirements, and review our analysis of existing platforms.

We have composed non-functional requirements for popular platforms like Netflix and Instagram — and you can take notions. To make software requirement documents clear and understandable, you need to use a pre-established tool for information collection and organization. Luckily, there are a lot of practical frameworks that can be used immediately.

Here are our top favorites used in SRS creation and further product management. The context diagram collects all the components in the system into a bigger picture. In the middle, you put the main parts of the system and add additional parts to the sides. This way, you see the system as a whole, not just the objects but also the relations between them as well. A significant advantage of a context diagram is that it provides clear visual representation.

With no graphic components, scanning a page document with product requirements would be a time-consuming task. Visually, functional decomposition is similar to the context diagram, but the structural principles between the two are different. You start creating a decomposition from the essential functionality and then break it down into structural parts.

These elements are, in their turn, broken down into structural sub-parts. This tool presents a hierarchic view of the system. You see which features are more important than the others and understand the dependencies in the project, which is very useful in the MVP development: you can see right away that the functionality should make it to the first product iterations by focusing only on the upper layers.

If the previous two tools depict the relationships between features within the system, this one displays relations between users and features. In this diagram, each user is seen as an actor who interacts with various features.

During the journey on the app, a user can take several paths of interactions. The scope of the use case diagram displays all possible routes in a concise and visualized way.

Sequence diagrams show how functionality and system develop over time. For each diagram, you define an actor — it can be a user, a feature, or a certain data type.

In the sequence diagram, you will identify how an actor moves through the system and what changes happen. Sequence diagrams can be used in functional requirements to define how a given feature changes over time or in regards to different user inputs.

In this example, the diagram depicts the path of an email notification. A similar tool can be used for any type of feature or data. These two diagrams help describe software functionality in relation to business processes. AS-IS diagram describes current processes.

It helps the entire team to understand how things are done in the current solution, identify problematic areas, and risks. Some processes are likely to be entirely intact, and you would like to keep them unaffected for future modifications.

AS-IS models feature applications, agents, and connected parties. This way, the diagram provides an outlook on users who execute the action, middlemen, and final stakeholders. It can also be used to define connections between various features or functionality and its inputs-outputs. The TO-BE diagram shows how existing processes can be revolutionized within your software. User stories describe actions that a user can perform with the application.

You can start with writing epic user stories that refer to general activities under normal conditions. These user stories describe big scenarios that involve a lot of actions. Once you have several epic stores, you can break them down to smaller scenarios, using decomposition. Mind maps come handy during brainstorming and teamwork.

You can use real-time mind maps tools that allow all team members and contributors to edit the SRS mind map. You can create a mind map for each section of the document. It will help you to get down the structure of the document and understand what components are crucial to your software. One of our favorite advantages of mind mapping is that it keeps the brainstorming process creative. The process of sketching and filling out a map is spontaneous, and it feels a lot less like a typical documentation activity.

This encourages team members to think out of the box. If you can make a visual out of your system requirements, customers will likely understand the logic behind your platform easily, too.