Software Development Life Cycle (SDLC): Phases, Models, and Benefits

What Is SDLC & Why Is It Significance?

SDLC: the full form is Software Development Life Cycle. Before building an application, engineers first create a plan. The second thing they do is design a blueprint. The next step they take is to write code based on the design. After this, testing is performed, followed by deployment.

The final mandatory step carried out even after launch is maintenance. Software developers follow this framework with all the steps from planning to maintaining software.

Why Is SDLC Important?

Software Development Life Cycle is an organized way to carry out work. Imagine a software development team performing their task. If the team starts with planning, builds a blueprint, and finally launches, they will make fewer mistakes before executing the final product. At the same time, expenses will be lower.

Now, let’s ponder why SDLC is essential: 

1. It Brings Structure & Clarity

SDLC has different steps involved, from planning, designing, coding, testing, and maintaining an application. Every member of a team is assigned their duties, along with when they have to do a certain task and what to do next. 

This process altogether creates clarity, instead of no one being aware of what they have to do. At the same time, everything flows systematically.

2. It Reduces Expenses & Saves Time

If every task is performed within the required duration, mistakes will be detected before the software is launched to users. If a team spots errors while planning and designing a blueprint, it would be easier for them to fix them than fixing them once the software is ready to be launched. 

3. Helps Identify Risks Early

A team can spot risks with the help of the Software Development Life Cycle (SDLC), even before they can affect a project. The possible risks that can affect a project are a shortage of money to carry forward the project, technical difficulties, and project delays. 

4. Aligns with Business and User Goals 

How will the software help people, and who all will use it? The software development life cycle helps a team working on building the software get answers to the above two questions.

5. Improves Visibility and Transparency 

By implementing the Software Development Life Cycle (SDLC), a team working towards creating software will be able to see how much work they have completed. In addition, they will also know how much is still pending. Project managers and clients can also track the progress of the project. They can also check whether the project is running as per the planned schedule and budget. 

6. Ensures Higher Quality and Security 

There is one step that is included in the SDLC: testing. This step helps to identify errors, protect user information, and ensure the software works properly.

 

Software Development Life Cycle Phases: Breaking down

There are 7 software development life cycle phases. Here are those:

Planning

The first phase of an SDLC life cycle is planning. The team involved in making software decides certain things. What kind of software are they going to build, what issue will it resolve, how much money will be poured into it, what will be the time duration to complete it, and what resources will be required? During planning, a team usually decides on these aspects. 

Requirements Analysis

Customers, business owners, and stakeholders are contacted to understand exactly what the software will do. These people who will use the software give their take on how the software should be, and the team takes notes. There are two types of requirements made, one is functional, and another one is non-functional. 

Functional requirements include what the software should do, and non-functional requirements include how well the software should operate. 

System Design

Once everything is on paper which are the goals, and requirements, the team sketches a blueprint of how the software will look and work. The team designs a homepage, decides how information will be solved, and which programming languages and technologies to use. 

Development (Coding / Implementation) 

Writing code is an important step that developers perform to convert the design into an actual software that works. They build the different features and connect them so that the software works as expected.

Testing

Once a software is developed, then it is tested to check its quality. During a testing phase, how fast is the software, is it safe to use, and nothing breaks when users use the software in unexpected ways is checked by the team. If an error occurs, the developer team fixes it before the software gets launched. 

Deployment

Once everything looks fine, the software gets launched. The software is launched to the real world either on a company’s server, a website, or an app store. A quick check is performed right before the software is released to make sure nothing breaks afterwards. Once it is released, people can use it. 

Maintenance and Operations

After launching the software, the developer cannot just sit and relax. They have to keep an eye on the software. Developers make sure the software is consistent in performance. They fix bugs if new ones arise, patch security holes, improve its performance, and introduce new features if required.

 

Types of Software Development Life Cycle Models

SDLC models are different ways to plan, develop, test, and launch software. These are the different styles in which a team runs the steps. The type of model depends on the project size, budget, requirements, and complexity. Let's understand the nine common SDLC models with simple examples.

Waterfall Model

This model follows a step-by-step approach. Once a step is completed, they don’t go back to change it. The team involved in building a project must complete one step and then move forward to the next. It is the best type of model for small projects that are uncomplicated and are unlikely to change. 

The drawback of the waterfall model is that making changes for a team can be difficult, they can take a lot of time to launch a software, and they even have to spend a hefty amount to do changes. 

V-Model (Verification and Validation Model) 

It is almost similar to the Waterfall Model, but the testing plans are written much earlier. For every development stage, the team plans a corresponding testing activity. This means testing is planned from the beginning rather than waiting until development is complete. This model works best for projects that need to be accurate, safe, and reliable. 

For example: Healthcare and aerospace software. The drawback is that it is difficult to make changes once the development has started. 

Iterative Model

In the Iterative Model, developers build a basic software first, and then make changes if they have to improve it. They improve the software by making changes, collecting feedback, and fixing problems. It is best for complex projects which require improvement from every now and then. In complex projects, the requirements aren’t clear from the beginning. 

So, this model is best suited for those large and complex projects, for example, a shopping app. The drawback of this model is that if improvements are made repeatedly, it can increase the duration and cost of developing software. 

Incremental Model

Developers build software in small parts. They add one new feature to the existing software until the software is completely ready. Users can use a completed feature before using the entire software. It is best for projects that can be divided into smaller parts, independent features. The only drawback can be that developers need a proper plan to make sure all individual features/parts work well together. 

Prototyping Model

In this model, developers build a basic sample or earlier version of a software before completing the final product. Users can use the sample and give their feedback. The team takes note of what the users like, what they need to improve, and what changes should be made. The model is best for projects where the needs of users or screen design are not clear.

The drawback of this model is that constant feedback can increase the duration and cost of development. 

Spiral Model 

The spiral model means developers work in loops. At every stage, developers look for potential risks that would have a huge consequence on the final result. They tackle the bigger risk first. It is best for large, expensive, and high-risk projects. The drawback of this model is that it can be expensive and complicated to manage. 

Agile Model 

A large project is split into smaller parts called sprints. Each sprint lasts one to four weeks. When a sprint is completed, developers review how it is working, and they also collect feedback from users. After this, they decide what has to be improved in the next sprint. It is best for projects where customers’ needs and requirements change again and again. The downside of this model is that making changes again and again can make the planning of a project difficult. Paperwork may receive less attention. 

DevOps Model 

Two teams or functions are combined in DevOps: Software development (Dev) and IT Operations (Ops). In this model, two teams work together throughout the process. The developer team starts creating software, and after that, the IT operations team will work on deploying it; however, that is not the case. Both teams work at the same time use automation to create, release, test, and audit software consistently.

This model is best suited for websites, cloud-based applications, and software that needs to be updated regularly. Its drawback is that it requires good teamwork, technical skills, and specialized tools. 

Big Bang Model 

This is the type of model in which developers don’t usually spend much time planning a project in detail. Whatever resources are available, including the ideas that they have, are enough for them to start writing code. Trial and error and experimentation get them the final result. Projects of small size, school assignments, and not-so-complex prototypes will fit best under this model. However, it is not recommended for large projects with complexity. Complex projects require planning, resources, more money, and a fixed duration to be completed.

 

DevOps & The Software Development Life Cycle

DevOps is a way of delivering software where both developers and the IT operations team collaborate instead of performing their tasks separately. In DevOps, Dev (Development) means the team that is responsible for writing code and creating software. On the other hand, Ops (Operations) means the team that is responsible for running, managing, and maintaining software.

For example, if a company is working on a project to make a shopping app. The development team will build features such as product searches and online payments. On the other hand, it is the duty of the operations team to make sure that the shopping website runs properly. The development and operations teams share responsibilities from planning to the daily running of software.

The three core principles of the DevOps approach are:

Collaboration:
Both a team of developers and IT operators work together by doing what they are good at. Both teams have their own responsibilities. 

Automation:
Running tests and releasing updates are some of the tasks that are performed almost every day. Computers tackle these kinds of tasks.

CI/CD:
Continuous Integration and Continuous Delivery. CI means developers write new code several times a day (every day), and it is automatically checked each time. Problems get caught immediately instead of piling up. CD means once the code passes the checks, it can be released to users quickly and safely, without a big stressful launch day.  

In the Software Development Life Cycle (SDLC), different steps are involved such as planning, designing, testing, releasing, and maintaining. One step at a time. However, in DevOps, all the steps take place continuously. If one feature is already released, another feature is being tested, another is being coded, and the live product is being monitored for problems.

What the team learns from watching the live software becomes the to-do list for what they work on next. It matters because the software is improved through many small, frequent updates instead of a few big, risky ones. That’s why apps like Netflix or Instagram can change things constantly without breaking.

DevOps is not a single method or a tool you can buy. It’s a combination of habits, tools, and a team culture built on working together and sharing responsibility.

 

Understanding DevSecOps In The SDLC

When security is built into every step of making software, it is called DevSecOps. The Sec in DevSecOps stands for security. Commonly, a security check of software would be done before releasing it to the real world. In this case, if security concerns arise, a team had to rework on big parts of a software, which would lead to delaying the project, and costing them a loss of money.

DevSecOps security checks happen in every phase of the SDLC, and not just in one step.

Code reviews are conducted, in which developers review code to avoid delays. A penetration test is also performed. This means hiring ethical hackers who break into software to find weak areas before real hackers do.

This helps to identify problems beforehand, when they are small and can be fixed at less cost. Because of this, there are fewer delays in launching software, as there will be no abrupt surprises at the end. The software made will be safe, as security checks are done at every step. As automation spots issues instantly, the fixing of issues can be done faster. The cost will be lower, as fixing flaws will be done much earlier before launching.

 

SDLC vs Agile vs Scrum: Key Differences

SDLC (Software Development Life Cycle) is a whole process of creating and maintaining software. It has different phases from idea of what the software will solve, how it will look like, developers writing code, testing, launching, and fixing it from time to time, and also updating it when needed. It is like an entire journey followed to make software.

Agile is a model of approaching software development. A large project is split into smaller parts called sprints. Each sprint lasts one to four weeks. When a sprint is completed, developers review how it is working, and they also collect feedback from users. After this, they decide what has to be improved in the next sprint.

Scrum is a framework that helps the team build software and organize Agile work. Scrum helps organize the work through short periods called sprints that last 1 to 4 weeks.

 

Potential Risks and Challenges in SDLC

Scope Creep and Changing Requirements

When clients and stakeholders ask to make repeated changes or add new features after the project has been started, scope creep occurs. Due to unexpected changes, the workload, time duration to complete a project, and cost required for development increase.

Poor Cost and Schedule Estimation

If a team estimates the cost, the time it will take to complete a project, and the resources needed to complete a project. If they estimate all three incorrectly, or any of the three incorrectly, it may lead to delaying of project, and budget problems.

Communication and Coordination Gaps

If team members don’t communicate properly, the project may be delayed. So, they have to rework many things. This is unnecessary, just due to misunderstandings.

Technical Debt and Poor Code Quality

When developers take shortcuts to complete software faster and do not follow proper coding practices, technical debt occurs.  This can lead to technical problems that are difficult to fix later and cost more.

Testing Limitations and Large Amounts of Data

Testing leads to fixing errors in the first place before software is launched in the real world. However, if the testing of software is not conducted under different circumstances, the company has to face some serious consequences.

User Resistance

If developers create software without understanding what the users want, there is a high possibility that users may not use the final product.

AI and Automation Risks

Developers should not completely depend on AI. AI tools can help developers generate code and perform repetitive tasks, speeding up development. But AI can also produce incorrect code and errors. A final check should be run by developers to avoid security weaknesses and errors.

 

Conclusion

Software Development Life Cycle (SDLC) involves various steps before launching software to users. From planning to resource requirements, testing, and monitoring, developers have to perform every step to execute the final output without mistakes. With 7 phases, there are different models. The models describe how phases of the Software Development Life Cycle (SDLC) are performed.

Although there are benefits such as identifying risks before launching software, there are also challenges like technical debt. Software Development Life Cycle (SDLC) is helpful to build a software, making fewer mistakes, at the same time saving money and time. But be careful to evaluate potential limitations that come with it.

Nonetheless, our organization, Sprintzeal, offers various courses running in 490 plus locations across the globe. It offers different modes of training, from classroom and online to corporate training. With 2 million+ global learners, our organization is reputed for providing 100 plus courses running daily. The trainer who teaches the concepts not only has theoretical knowledge, but also has real-world knowledge. The courses related to this topic are DevOps and DevSecOps certifications.

Devops Certification Training

DevSecOps Foundation

 

FAQ’s on Software Development Life Cycle

1. Is the Software Development Life Cycle outdated?

Many companies refuse to use the Software Development Life Cycle (SDLC) with an outdated approach, such as following strict rules and steps that cannot be changed. Companies that need to update their software constantly and also evolve it usually discard the idea of SDLC.

2. How to explain Software Development Life Cycle (SDLC) when asked in an interview?

When an interviewer asks about SDLC, start with the definition. After this, explain the phases and SDLC models as well. Don’t forget to explain how to apply SDLC in real life.

3. Example of the Software Development Life Cycle?

The end goal of the project is to create a mobile application. The mobile app will help customers of a bank to see their balance, make payments, and transfer money. Here are the needs: The app follows the same rules as a bank would follow in different regions and countries.  In addition, the app can also handle 100,000 people using the app at the same time.

4. SDLC meaning vs Agile meaning?

Cycle (SDLC) is that framework, or you can call it a step-by-step process. From planning to maintaining software, Software Development Life Cycle (SDLC) covers everything. On the other hand, Agile is a method for creating software. A project is broken down into small parts called sprints. A sprint lasts up to 1 to 4 weeks. When a sprint is completed, developers review how it is working, and they also collect feedback from users. After this, they decide what has to be improved in the next sprint.