Dec 17, 20244 min read

What is the Software Development Life Cycle (SDLC)

Software Development Life Cycle is the step-wise approach to design, develop and test software applications and ensure their quality and functionality. It involves different activities to deliver bug-free software applications in less time and with minimal effort. Technically, you can understand SDLC as an optimized strategy for developing software applications.
For every software application development, its completion in a pre-defined time and budget is equally important as ensuring its quality. To achieve this, you should work in an organized and structured manner to keep track of the progress in software development.
Here comes Software Development Life Cycle as the solution. It is a framework that defines the stages and activities of the software development process. You can follow this process to design, develop, test and deploy software .

Phases of the SDLC Model :

There are seven phases of the SDLC:

The planning phase involves project and product management.

This may include:

Ideally, Project Managers and Development staff collaborate with Operations and Security teams to ensure all perspectives are represented.

The outcomes of the planning phase includes:

The company must communicate with tech teams to convey their requirements for new development and enhancement. The requirements phase gathers these parameters from business stakeholders and Subject Matter Experts (SMEs.).
Architects, Development teams, and Product Managers work with the SMEs to document the business processes that need to be automated through software. The output of this phase in a Waterfall project is usually a document that lists these requirements. Agile methods, by contrast, may produce a backlog of tasks to be performed.

Once the requirements are understood, software architects and developers can begin to design the software. The design process uses established patterns for application architecture and software development. Architects may use an architecture framework such as TOGAF to compose an application from existing components, promoting reuse and standardization.
Developers use proven Design Patterns to solve algorithmic problems in a consistent way. This phase may also include some rapid prototyping, also known as a spike, to compare solutions to find the best fit. The output of this phase includes:
Design documents that list the patterns and components selected for the project.
Code produced by spikes, is used as a starting point for development.

This phase involves the actual coding to produce the software itself. Depending on the methodology, this phase may be conducted in time-boxed “sprints,” (Agile) or may proceed as a single block of effort (Waterfall).
Regardless of methodology, the aim is for development teams to produce working software as quickly as possible. Business stakeholders should be engaged regularly, to ensure that their expectations are being met. The output of this phase is testable, functional software.

Testing
The testing phase of the SDLC is one of the most important. It is impossible to deliver quality software without testing. There is a wide variety of testing necessary to measure quality:
Code quality.
Unit testing (functional tests).
Integration testing.
Performance testing.
Security testing.
The best way to ensure that tests are run regularly, and never skipped for expediency, is to automate them. Tests can be automated using Continuous Integration tools, like codeship. The output of the testing phase is improved software, ready for deployment to a production environment.

The deployment phase is, ideally, highly automated. In high-maturity enterprises, this phase is almost invisible; software is deployed the instant it is ready.
For enterprises with lower maturity, or in some highly regulated industries, the process involves some manual approvals. However, even in those cases it is best for the deployment itself to be fully automated in a continuous deployment model. Application Release Automation (ARA) tools are used in medium and large-size enterprises to automate the deployment of applications to Production environments. ARA systems are usually integrated with Continuous Integration tools. The output of this phase is the release to Production of working software.

The operations and maintenance phase is the “end of the beginning,” so to speak. The Software Development Life Cycle doesn’t end here. Software must be monitored constantly to ensure proper operation. Bugs and defects discovered in Production must be reported and responded to, which often feeds work back into the process. Bug fixes may not flow through the entire cycle. However, at least an abbreviated process is necessary to ensure that the fix does not introduce other problems (known as a regression).

Methodologies of Software Development Life Cycle

The two best-known methodologies within the SDLC are Waterfall and Agile. Below is a brief explanation and how they relate to the SDLC.

The Waterfall Model is one of the most crucial and widely accepted SDLC models. In this method, software development is done in small phases with specific goals that the team requires to achieve. The phases of the Waterfall Model include requirement analysis, design, development, testing, deployment, and maintenance.
Each phase involved here must be completed before moving to the next incremental approach. This is because the outcome of previous phases functions as input for the next and is thus regarded as a sequential-linear model. Therefore, you can easily monitor the feasibility through each step of the development of software development.

Agile Model is the crucial software development method enabling the interaction of the testing and development phases of the SDLC. The development process is broken into small iterations called sprints.It values adaptability and responsiveness to change in the software application. It is designed to be used in software applications without fully defined requirements, or the end user’s needs may change over time.