What is SDLC

What is SDLC? Understanding Top Fundamentals, Phases, and Methodologies

The term SDLC has been galvanizing more traction than ever. But, what is SDLC? Emerging as a cult industry practice, it talks about establishing a predictable and iterative process for each stage of software development. And, as noises around integrating security earlier in system development lifecycle phases grow louder, SDLC is here to rock the boat, one wave at a time.

The Software Development Lifecycle, also SDLC, is a model for managing the development of software products and is primarily fragmented into stages, including planning, documentation, development, testing, and release. The entire process is a composite of various complex and diverse tasks that require an array of skills and more profound domain knowledge. Headhunters are always on the lookout for world-class programmers or coders, software engineers, and software developers who can help them empower their organizations with software solutions that are agile, robust, and a future fit. For the most part, SDLC relies on the dynamic interaction of these roles, which often overlaps and varies greatly.

To say that the software sits at the heart of an organization’s operational ability would be an understatement. Such a solution is an organization’s spine, providing speed and scalability to grow and get ahead. When companies compete today, the software is an incentive to help them create a bouquet of services and products better than their competitors. 

Unfortunately, despite the mission-critical nature of the software, it doesn’t capture as much attention as required from the C-suite. Software engineers rarely have a say at the table, and software strategies are mulled over and defined two or three layers down in the hierarchy. This is mainly because software development is often seen as a cost center, something to be minimized and not prioritized. But as we have seen time and time again, neglecting software can have dire consequences for businesses.

  • Organizations that don’t plan and push down investments in software development risk falling behind in the age of tech disruption. 
  • Without a solid software foundation, enterprises can't deliver exceptional customer service and experience, more so in today’s era of intelligent customers who want everything everywhere and in a snap.
  • The software solutions improve productivity, save costs, and lead employees to free themselves from the grind to handle more strategic priorities. Without software solutions in the picture, organizations will face challenges, such as higher costs and lower margins. 

 Software innovation is advancing at warp speed and transforming the dynamics of the business landscape as we speak. Enterprises that acknowledge the wave and stay at pace tend to grow 5X faster than laggards. Software development must now be considered an avenue of interest and not ancillary in the grand scheme of things. 

What are the Seven Phases of SDLC?

Software development is an iterative process that involves designing, coding, testing, and deploying a software application or system. This process takes several different system development lifecycle phases, which are described below.

  1. Planning Phase

    The planning phase in a software development life cycle (SDLC) is where the team lays out the specifics of their project - from the requirements gathering to the timeline. This is an important stage as it allows everyone on the team to understand their role and responsibilities and ensure that the project is on track. By ensuring that everyone is on the same page, the planning phase can help avoid misunderstandings and delays later on.

    During this phase, the concerned development team gathers inputs from stakeholders and coalesces this information into a comprehensive statement of software development requirements. Besides, the team zeroes in on the resources required to meet the criteria and determines cost estimates.

  2. Design Phase 

    After the system analysis and functional requirements gathering under the Planning phase, the very next step in the software development life cycle is the Design phase. Many functional and non-functional aspects like IT infrastructure, system architecture, pseudo-code, screen layouts, the user interface, data models, entity relationship diagrams (ERDs), and other necessary documentation are covered in this phase. 

  3. Coding Phase

    The coding phase in an SDLC focuses on translating the system design into code written in a specific programming language. Programmers are called upon to undertake the task and are asked to design a code significantly reducing testing and maintenance efforts. This is the phase where the team works on the code requirements determined earlier and lays the groundwork for building the software. During this phase, the team creates the user interface (UI), business logic, data structures, and other components that make the software. They also generate any documentation needed to support the project.

  4. Testing Phase

    The testing phase in a software development life cycle (SDLC) is a crucial stage that helps ensure the software meets the required standards. During this phase, the various components of the software are tested to ensure that they work as expected and conform to the specifications set out in the SDLC. Developers rectify any issues found during this testing phase, and a new version of the software is produced.

    Across the testing phase, a series of functional and non-functional assessments are conducted. Automated testing has gained more momentum lately since the process ensures a secure and continuous run of the software and produces correct data for everyone to consider and derive conclusions. One of the prerequisites for automated testing is continuous integration tools. 

  5. Release & Deployment Phase

    In a secure SDLC, the release phase includes activities associated with the team packaging, managing, and deploying releases across different environments. After things go smoothly in the release phase, the development team moves toward the deployment phase, where the software is officially deployed into the production environment. Once the product is rigorously tested and has passed each testing phase, it becomes ready to go live. 

  6. Operation Phase

    Utilizing the software in its production environment constitutes the operation phase. The operations manager is responsible for tracking performance metrics and regularly updating whether the software moves in the right direction. 

  7. The Monitoring Phase

    This is where various software elements are monitored for performance, user experience, new security vulnerabilities, and more. By investing time in this phase, enterprises identify issues that may occur during the run and pull the strings necessary to achieve optimal performance. 

System development lifecycle phases

                                   Image - 1: Seven Phases of Software Development

What are the Top SDLC Methodologies?


    Waterfall methodology is one of the oldest, long-established methodologies, recommending a more uniform software development approach based on discipline. It involves an organized and sequential process that helps project managers track the progress from start to finish. Adhering to the waterfall model ensures that all required steps are completed before moving to the next stage. While the waterfall methodology effectively achieves this goal, it can be difficult to adapt when flexibility is needed. Panning out change can be problematic as such an action can affect the cost, delivery time, and software quality simultaneously. 


    Agile methodology focuses on iterative, cross-functional collaboration to deliver rapid innovation in response to new business demands. Enabling flexibility and adaptive planning is one of the key themes of the agile software development model. It emphasizes quick feedback and continuous delivery of the working software at the end of every cycle. The agile model recommends dividing a project into phases based on requirements and functionality, and each phase is time-boxed into sprints to build momentum towards goals.

    An iterative software development methodology focuses on building solutions continuously by testing and modifying them. It involves taking small steps (iterations) and making changes to a product quickly so that it becomes better and better over time. This approach is often used when organizations develop a new product because it allows them to test different ideas and see which ones work best quickly.
  • LEAN 

    The LEAN methodology is an ideal fit for leaders looking to weave the continuous improvement culture into the fabric of their organizations. It relies on four principles:

    1-Locate all work in a system where it can be measured. 
    2-Estimate the work required to do a task and ensure all resources are available. 
    3-Break the task down into manageable parts and schedule them accordingly. 
    4-Define the quality requirement for each part of the task and ensure these are met.
    5-Respond quickly to changes and transform the product for the evolving world. 

    The V-shaped methodology suggests that the verification and validation phases run parallel, ensuring minimal issues and high performance of the software. The model runs in a V-shape, meaning that every verification stage has a validation stage, and each stage feeds information back into the previous stage. This helps ensure that all aspects of the system are appropriately validated, and any issues are identified and corrected. Besides other upsides, the V-shaped methodology helps prevent software projects from becoming too big or unwieldy. 

    A spiral methodology is a problem-solving approach that focuses on systematically working through a problem from the end to the beginning. Organizations can efficiently work through all obstacles and challenges by starting with the end goal in mind. 

The Role of Security in SDLC 

Back in the day, security was considered a side issue in the software development lifecycle. Matters pertaining to it were tackled during the last leg more as a standalone responsibility. This never stirred up trouble because development cycles lasted months and even years. The shortcomings of this post facto approach were drastic. Since vulnerabilities were not discovered early in the process, they persisted far too long across the lifecycle to harm the software’s performance. Timelines doubled up, making it challenging for enterprises to lead in the market. With issues worming in, chunks of money used to go down the drain in fine-tuning the basic releases only. 

However, today, it is a well-understood fact that security cannot be an afterthought and must be baked in as soon as the project receives the green light. CTOs know that vulnerabilities can be discovered and mitigated incrementally by incorporating security practices early in the software development lifecycle, making more room for cost savings.

The SDLC where security is given prime importance and dealt with from the get-go is called a ‘Secure SDLC’ or security systems development lifecycle. During a secure SDLC, defining the risks to the organization, designing adequate controls and processes, testing and monitoring the effectiveness of these controls, and incident response planning are carried out like clockwork. Integrating security with SDLC in a ground-up approach has been easier with the modern application security testing tools. 

 Benefits of Embracing Security Systems Development Lifecycle

How Does Kellton Transform Software Development Experience?

Kellton brings the in-depth expertise of the leading software development practices aligned with the agile development approach, enabling businesses to make the right decisions. Our experts help them respond to all the necessary strategic initiatives, from the cloud-migration path to adopting the right cloud platform and microservices/container architecture. This way, we help our clients achieve a shorter time-to-market while reinventing their core software-defined technology capabilities. 

What's more, Kellton delivers next-gen solutions with accelerated product-management excellence and agile transformation of legacy products in the shortest possible time through our effective product management capabilities. Our future-ready software products are powered by a frictionless human-centric design, enabling a competitive edge for our clients. 

As your transformation partner, we always ensure innovation across the software development lifecycle, and to achieve the same; our team adopts best-in-class product development and product delivery practices, which primarily include DevOps, A/B testing, API-based architecture, analytics and telemetry, automated performance management, mature open-source software, and libraries. Kellton delivers accelerated business value by automating testing and integrating test-driven development into the entire SDLC with speed and quality.