Software development can be a mammoth task, especially for complex projects. If you don’t manage the process correctly, it could spiral out of control and your software could be released before it’s glitch-free.
The best way to avoid this is to follow a step-by-step framework that ensures maximum productivity, product consistency, and customer satisfaction – which is where the software development life cycle (SDLC) can help.
What is the SDLC?
The software development life cycle is a sequence of activities covering a project from planning to maintenance. The aim is to create and deliver high-quality software in the shortest possible time.
The SDLC is divided into separate tasks, such as identifying requirements, designing code, deploying the product, and carrying out maintenance. This approach can be used to make any size or type of software project more efficient.
The method is used in conjunction with various software development models, which we’ll come to later.
Benefits
Because SDLC provides a road map for the project, your team will know exactly what needs to be done. With proper planning and a step-by-step approach, it’s easy to see if the project is on track.
Including a testing phase means that bugs are spotted early, which reduces costs. And the software is designed based on end-user needs, so it’s more likely to satisfy customers.
What are the stages of the SDLC?
The SDLC can be broken down into five, six or seven distinct stages (we’ve used six). No matter how many you use, they have to be carried out in order— you can’t skip a stage.
- Strategy
The planning stage starts with research into the requirements of clients and stakeholders. Who will use your software, what problems does it address, and how does it deliver value? Consider implementing a CRM here to identify customer preferences.
At this point, you should create a Software Requirements Specification (SRS) document to detail the required features and timeline, along with any anticipated risks or problems. This will then be approved (or edited) by clients and stakeholders.
- Design
The SRS document is a basis for the SDLC design phase, which generates another document called the Design Document Specification (DDS). This is created by the product architects, defining the technical components needed to deliver on the requirements.
It should describe the product features more thoroughly, and includes budget and time estimates for the design. Again, the DDS must be approved by the client and stakeholders, who may offer feedback to improve it.
- Development
This is the longest stage of the life cycle, as it’s where the actual software coding takes place. Tasks are usually separated into units and carried out by different developers using various programming tools.
Collaboration and communication are crucial at this stage, as developers work with QA (quality assurance) testers and project managers to make sure they have a standardized and testable version of the code.
- Testing
In the testing environment, QA teams check functionality and look for defects. Some teams use unit testing, where developers test the part of the code they’re working on instead of waiting until all development finishes.
If issues are found, the product goes back to the developers before being tested again. This stage is repeated until everyone agrees that the software is ready. Testing can’t guarantee a perfect product, but it minimizes the risk of bugs and saves you the cost of future fixes.
- Deployment
Once testing is complete, the product can be rolled out to the market. It’s typically accompanied by release notes that describe the features of this particular version.
Sometimes it’s initially deployed in a testing or staging environment, or released in beta (if you want to know what is beta testing in software testing, it’s when end-users try the product before the official launch).
- Maintenance
The final stage is maintenance, which must continue for as long as the product is on the market. This includes launching updates, fixing any glitches or bugs that were missed, or adding extra features at the behest of stakeholders.
You should also measure reactions to your product and improve the user experience. For instance, if you’ve created software for call center training programs, ask for feedback from call centers after they’ve used it for a couple of months.
Common SDLC models
There are plenty of SDLC models to choose from. Each follows the same basic stages, but some are more flexible than others. Your choice will depend on the size and skills of your team, the complexity of the project, and your business requirements.
Waterfall model
This is the simplest and most rigid model. Tasks must be completed in a strict sequential order, each cascading information into the next (hence the name). The model is documentation-heavy, with separate detailed plans for each stage.
This enables you to evaluate each task and ensure the project is on track. But if you hit a roadblock in one phase, the process grinds to a halt because you can’t move on until it’s complete. Any changes can be pretty expensive, and it produces quite a lot of documentation.
V model
Named for the parallel V structure it follows, the V model is similar to Waterfall as you work on one stage at a time. However, the stages are divided into Verification and Validation brackets, and there’s more emphasis on testing.
In fact, testing is included in every step, including unit, integration, and system testing. Again, you benefit from robust planning and continuous evaluation, but this model has the same drawbacks as Waterfall.
Iterative model
Here, the project is broken down into smaller tasks called iterations. Each of these passes through the SDLC stages, but the structure is flexible enough to permit small changes along the way. You can even work on a couple of iterations simultaneously.
It’s easy to measure progress, and to keep clients and end-users happy as the value of your software is immediately obvious. However, the lack of specific requirements can cause confusion.
Prototyping model
The aim here is to create working prototypes with just enough features for users to try them out, then deploy them swiftly and gather feedback. There are four types of prototyping: rapid, evolutionary, incremental, and extreme.
This model can be tricky to manage, and you can end up wasting time and money if you don’t get it right—but the advantage is that any defects can be spotted very early in the process.
Agile model
If you want a model with complete flexibility, Agile is for you. There’s limited planning and teams are expected to embrace change and adapt as they go.
Agile also uses client feedback as an essential component, so you can adjust your product to meet customers’ needs. For instance, you could ask clients to share the results they get from using artificial intelligence in customer service.
This reliance on client input means projects can go off-track, while the lack of documentation means you don’t have a clear picture of the end product.
Spiral model
This contains aspects of the prototyping and waterfall models, but it’s super-flexible. Basically, you run the SDLC stages multiple times, with feedback and improvements after each “spiral”.
It means you can add extra features if required, while the ongoing evaluation should lead to a better product. However, good management is needed to ensure that teams are prioritizing tasks appropriately.
Big Bang model
The Big Bang model sees teams operating on the fly, with barely any planning. Developers are required to understand and implement requirements as they arrive, concentrating all available resources on development and coding.
It’s highly flexible and easy to manage, but it also brings high risk—it can end up costing a lot of money if the sketchy requirements are misunderstood. As such, it’s more suited to smaller projects and teams.
DevOps model
DevOps emphasizes collaboration in the workplace, especially between the development and operations teams. Whereas in the past they worked separately, in this model they coordinate their efforts from the beginning, with an “everyone is responsible” mindset.
The aim is to speed up the software life cycle, using ongoing feedback and process improvement to facilitate continuous delivery and integration (the CI/CD pipeline). Automated testing and deployment are often used.
Best practices in SDLC
No matter what method you use, there are a few best practices to keep in mind.
Research
Ensure that you carry out thorough research, so that you get to know your audience and what they want from the product. For example, if a client is deciding between call vs contact center, give them software with features for both.
Planning
You know what they say: failing to plan means planning