What is Software Development Life Cycle (SDLC)?

By Yogesh

Software development life cycle (SDLC) is a structured way utilized in software engineering to build software systems that involves several steps: planning, gathering required information, design, code, test, deployment & maintenance.

Encompassing a series of phases, each with defined activities and deliverables, it is aimed at minimizing the project failure, efficient and effective development of high-quality software solutions that meet the customer demands.

Why is SDLC important?

SDLC is the basic framework that is needed to build software applications. By clearly defining the software development life cycle, a software development firm can develop a seamless information structure and successfully reach its goal of building a functional application.

Here are the various attributes that justify the benefits of SDLC:

Universal Relevance: SDLC adapts to any project size or complexity, providing a structured approach.
Structured Framework: Offers clear milestones and effective management of scope, timelines, and resources.
Streamlined Process: Breaks development into manageable phases, prioritizing tasks and tracking progress.
Quality Assurance: Ensures high software quality through rigorous testing at each phase.
Risk Mitigation: Identifies and mitigates risks early, reducing project failure chances.
Cost Efficiency: Minimizes unnecessary costs by avoiding rework and late changes.
Timely Delivery: Sets realistic milestones, ensuring on-time project completion.
Stakeholder Involvement: Engages stakeholders throughout, enhancing satisfaction and buy-in.
Adaptability: Models like Agile and DevOps adjust to changing requirements and market dynamics.

How does SDLC Work?

The Software Development Life Cycle (SDLC) divides the development process into 7 distinct phases: Planning, Analysis, Design, Coding, Testing, Deployment, and Maintenance. Each of these phases performs a special function and adds value to the application. We take a closer look at these stages of software development to know how the SDLC works.

Planning

During this phase, a collaborative effort from the key members of the software development team and stakeholders is required to ensure that all perspectives from both sides have been covered. In this process, the project manager charts out a plan that comprise the following steps:

Project Initiation: Define the project scope, objectives, and deliverables in consultation with stakeholders. Propose alternative solutions for objectives and specific problems.
Resource Allocation: Identify and allocate human, financial, and infrastructure resources required for the project. Conduct cost estimation analysis and have a course for the implementations of proposed changes.
Risk Assessment: Identify potential risks and uncertainties associated with the project and develop mitigation strategies.
Schedule Development: Develop a project schedule outlining key milestones, activities, and dependencies.
Requirement Prioritization: Prioritize requirements based on business value, technical feasibility, and project constraints.

Initial Requirement Gathering (Analysis)

Since the objectives have been clearly set at the planning phase, related facts gathering and interpretation of those facts are done at the requirement gathering phase. Here, a software development company analyzes the project goals with the end user information needs. The purpose of the analysis is to remove discrepancies and set complete user-requirements.

Once the plan is ready, the team proceeds to gathering requirements, where business analysts translate business requirements into technical requirements. The process includes:

Elicitation: Obtain end-user requirements through interviews, face-to-face interactions, observations, surveys and questionnaires.
Analysis: Analyze goals and objectives, and factors that can cause risks and create challenges and make strategies to avoid those challenges when working.
Prioritization: Prioritize requirements based on business value, criticality, and feasibility. Move ahead and prepare software requirement specification (SRS) for the next process.
Documentation: Document requirements using tools such as use case diagrams, user stories, and requirement traceability matrices.
Validation: Validate requirements by conducting reviews, walkthroughs, and prototyping sessions with stakeholders.

Design and Prototyping

The effects of your hard work in the first two phases will be visible at the design and prototyping phase of the SDLC process. The minute you have planned and gathered requirements, the stronger your designing team will come out at this phase, as the design process uses the set patterns for application architecture and software development.

The previous stage and designing offers the further direction, as 56% of defects are introduced during the requirements and design stage. So, the more careful you are, the more perfect direction you will offer to your project. A series of steps that need to be determined at this phase of the software development life cycle is the creation of screen layout, process diagrams, pseudocode, and documentation.

If you are hiring software developers from reputed software development companies, make sure to check how closely their designing team and software development team works, which is very crucial for the software application success. This phase covers the following stages:

Architectural Design: Define the overall architecture of the system, including components, layers, and communication protocols.
Detailed Design: Develop detailed design specifications for each component, specifying interfaces, data structures, and algorithms.
Database Design: Design the database schema, including tables, indexes, relationships, and constraints.
User Interface (UI) Design: Design the user interface layout, navigation flows, and interactive elements using wireframes or mockups.
Security Design: Designs define security mechanisms such as authentication, authorization, encryption, and data protection.

Coding

This is a cornerstone phase on which hinges the overall success of the project. In this phase of the software development life cycle, codes for the application are written. It is the actual “development” phase of the software where an idea of the software is transformed into a functional, efficient software program.

Regardless of the methodology, the key objective of this phase is to acutely follow the design patterns and documentation provided by the design team and develop a functional software. The process comprise the following stages:

Coding: Write source code following coding standards, naming conventions, and style guidelines.
Unit Testing: Develop unit tests using testing frameworks such as JUnit, pytest, or NUnit to verify the behavior of individual code units.
Integration: Integrate code changes into the main codebase frequently using version control systems like Git, Mercurial, or Subversion.
Code Review: Conduct code reviews to ensure code quality, consistency, and adherence to design specifications.
Continuous Integration (CI): Automate build and test processes using CI/CD tools like Jenkins, Travis CI, or CircleCI to detect integration issues early.

Testing and Integration

When a software development firm reaches this software development life cycle phase means they are very close to the end-consumers. What they need to keep in mind is to bring all the pieces of the software together and test the software from the perspective of users.

Quality analysts test the software application for bugs, errors, and interoperability. They need to come up with a winning strategy for software testing to make the software bug-free or at least try removing major bugs that can impact the usability of the software. Different types of testing include:

Certification testing	Documentation testing
Beta testing	Functional Testing
Localization Testing	Usability Testing
Change related Testing	UI Testing
Recovery Testing	Compatibility (Configuration)
Performance Testing	Testing

So, once the code is ready, the team proceeds to executing different tests so as to adhere to requisite quality standards. The process comprise the following steps:

Test Planning: Develop a test plan outlining test objectives, scope, resources, and schedule.
Test Case Design: Create detailed test cases covering functional, non-functional, and edge cases based on requirements and design specifications.
Test Execution: Execute test cases manually or automatically using testing tools like Selenium, JMeter, or Postman.
Defect Management: Report defects found during testing using defect tracking systems like Jira, Bugzilla, or Trello, and prioritize them for resolution.
Regression Testing: Perform regression testing to ensure that code changes do not introduce new defects or regressions in existing functionality.

Deployment

Now that you are close to the software release cycle, automation rules at deployment phase, although in enterprises with low maturity levels, the process of manual approval still exists.

There are several Application Release Automation (ARA) tools which are used to automate the deployment process. Commonly, these tools are integrated with continuous integration tools to produce working software. Finally, the tested product is installed and deployed in the client environment via the following steps:

Environment Setup: Configure deployment environments including development, testing, staging, and production environments.
Packaging: Package the software into deployable artifacts such as executable binaries, Docker containers, or installation packages.
Deployment Automation: Automate deployment processes using tools like Ansible, Puppet, or Chef to ensure consistency and repeatability.
Rollback Plan: Develop a rollback plan to revert changes in case of deployment failures or issues.
Monitoring and Alerting: Set up monitoring and alerting systems to track system health, performance, and availability post-deployment.

Maintenance

Maintenance is an ongoing life cycle phase in software project management. Through this process, a software development company takes effective measures to ensure that the software is meeting its objective and does not become obsolete. Bug fixes are also part of maintenance, ensuring that new fixes do not introduce new problems.

A long-term support and assistance plan is essential for sustainable functioning of the application. Through the following steps, the maintenance phase supports this requirement:

Incident Management: Respond to incidents and service requests raised by users through a helpdesk or ticketing system.
Bug Fixing: Analyze and debug reported issues, and develop fixes or workarounds to resolve them.
Performance Tuning: Monitor system performance metrics and optimize code, configurations, or infrastructure as needed.
Patch Management: Apply patches and updates to address security vulnerabilities or software bugs.
Knowledge Management: Maintain documentation, knowledge base articles, and FAQs to assist users and support teams.

Major SDLC Models

A professional software development agency will always choose the most suitable SDLC model based on the project scope and needs. Here are the 9 most common SDLC models: waterfall, iterative, spiral, agile, scrum, kanban, v-model, RAD and DevOps.

Waterfall

Waterfall model is a sequential approach to software development, where each phase, including requirements gathering, design, implementation, testing, deployment, and maintenance, is completed before moving to the next. Extensive upfront planning and documentation are its core aspects which make it suitable for projects with stable and well-understood requirements.

But then, due to its rigid structure it is less adaptable to changes during the development process, and issues discovered late in the cycle, which can be costly to address. Despite these limitations, the Waterfall Model still remains valuable for projects when they have clearly defined objectives and there is minimal uncertainty.

Iterative

It breaks down the software development process into small iterations or cycles. By delivering working software increments at the end of each iteration, it offers flexibility and adaptation to changing requirements. So, the approach promotes continuous improvement and refinement based on feedback received throughout the development process.

By providing early and frequent releases, the iterative model mitigates risks associated with uncertainty while making sure that the final software product aligns closely with customer expectations.

Spiral

The Spiral Model combines elements of both waterfall and iterative approaches, emphasizing risk analysis and mitigation throughout the development process. It iteratively builds and refines prototypes through multiple cycles or spirals, with each iteration addressing identified risks and uncertainties.

The model is particularly suitable for large, complex projects with high levels of uncertainty, as it allows for progressive elaboration and risk-driven development. By incorporating feedback loops and risk management activities at each stage, it assists in early detection and mitigation of potential issues, which is how it guarantees the project success.

Agile Model

The Agile Model is basically a class of flexible and adaptive approaches to software development that emphasizes collaboration, customer feedback, and iterative development. With a focus on responding to change and embracing uncertainty, it promotes rapid and incremental delivery of working software.

Agile methodologies, such as Scrum and Kanban, enable cross-functional teams to work collaboratively in short development cycles known as sprints. We shall look at these models in detail below. Regular feedback loops and continuous improvement processes are key to agile philosophy that drives product evolution in tandem with changing requirements and customer needs effectively.

Scrum

Scrum is an Agile SDLC framework that organizes work into fixed-length iterations called sprints, which typically last 2-4 weeks, depending on the project. A key part of Scrum is that cross-functional teams collaborate to deliver a potentially shippable product increment at the end of each sprint.

This way, by focusing on delivering small, manageable increments of functionality, Scrum lets teams adapt to changing priorities and requirements efficiently. Scrum ceremonies, including daily stand-up meetings, sprint planning, sprint review, and sprint retrospective, improve communication, bring transparency, and continuously add value to the application.

Kanban

Kanban is a Lean approach to software development that visualizes the workflow on a Kanban board, with tasks moving through different stages from backlog to done. Derived from the idea of Kanban implementation in manufacturing, it limits work in progress (WIP) to improve flow and efficiency, highlighting bottlenecks and areas for improvement.

As a project management approach, Kanban promotes continuous delivery and encourages teams to prioritize work based on customer needs and feedback. As it provides real-time visibility into the status of work items, Kanban reduces lead times, and promotes a value-driven culture.

V-Model (Verification and Validation Model)

Based on the idea of early verification and validation of requirements, designs, and code, it is a sequential process model that pairs each phase of development with a corresponding testing phase.

Aiming to meet the specified quality standards, the V-Model aligns testing activities closely with development activities. The systematic verification and validation of each deliverable against predefined acceptance criteria is the core aspect of the V-Model, through which it brings reliability, predictability, and maintainability to the project.

RAD (Rapid Application Development)

Rapid Application Development (RAD) is an iterative and incremental approach to software development that prioritizes rapid prototyping and stakeholder involvement. Leveraging user feedback and aggressive cross-functional collaboration are key steps undertaken to accelerate the development process and reduce time to market.

Implementation of iterative development cycles, reusable components, and automated tools streamline the development effort in RAD. The team delivers working prototypes early and frequently to allow stakeholders to visualize the final product and provide timely feedback that makes RAD a responsive and customer-centric development process.

DevOps

DevOps is a cultural and technical approach to software development that integrates development and operations processes for continuous delivery and deployment. To streamline the software delivery pipeline, DevOps emphasizes automation, collaboration, and feedback loops.

With its core practices such as infrastructure as code, continuous integration, continuous delivery, and monitoring, teams release software reliably and with reduced risk. The key dimension of DevOps is that it breaks down silos between development and operations teams, and promotes shared responsibility and accountability.

How to Choose the Right Software Development Lifecycle (SDLC) Model for Your Project

We looked at the major software development models, and each of them comes with its own applicability advantages. To offer you a clearer direction here are 11 elements that you must consider to choose the right SDLC model for your software development project:

Project Requirements

Understand your project requirements thoroughly for choosing the right development model. Know what are its scope, objectives, and constraints to select a model that aligns with the project’s goals, and takes into account all necessary features and functionalities.

Team Expertise and Stakeholder Preferences

Consider the team’s expertise as well as the preferences of clients. The chosen model should match the team’s skills and experience while accommodating the level of involvement and feedback throughout the software development process.

Complexity and Size of the Project

Evaluate the complexity and size of the project to determine the most suitable model. Complex projects with multiple dependencies might benefit from iterative models, while straightforward projects with clear requirements might be best served by more linear approaches.

Need for Flexibility and Adaptability

Assess the project’s need for flexibility and adaptability. If requirements are likely to change frequently, an agile model that allows for quick adjustments is preferable. On the contrary, for software development projects with stable requirements, you can choose to implement the waterfall approach.

Risk and Uncertainty

Identify potential risks and uncertainties to choose a model that provides effective project management and mitigation strategies. Models that incorporate risk assessment and iterative review help in navigating and reducing project risks.

Delivery Timeframe Considerations

Consider any deadlines or time constraints for project delivery. If there are strict timelines, models that support incremental or phased delivery are best as they help track progress in a timely manner.

Documentation and Compliance Needs

Determine the level of documentation and compliance required. Some models, like Waterfall, emphasize thorough documentation, which is beneficial for projects with stringent regulatory requirements or complex needs.

Alignment with Client or Market Needs

Understanding client preferences and the standards of the industry and then arrive at your choice of a model that perfectly meets external demands and improves project acceptance.

Resource Availability Assessment

The chosen model should fit within the team’s capabilities and make all required technologies and infrastructure rightly accessible.

Long-term Maintenance and Support Planning

Projects requiring ongoing updates and user assistance benefit from models that facilitate easy maintenance and support mechanisms post-deployment.

Leveraging Historical Data and Past Experiences

Check previously executed projects to offer a clear direction for your upcoming endeavor. Analyze what worked well and what challenges were faced in similar projects to obtain insights for selecting the most effective software development approach.

Conclusion

And as we saw, the SDLC is not just a methodology but a strategic framework that guides the software development process through its lifecycle. Each SDLC model is built to work for a particular project scenario. So, before making a choice of a SDLC model, you must examine its applicability to the project.

Also, the software development life cycle management is the key responsibility of project managers and business owners. To make the system flawless, it is crucial that all the stakeholders come together to discuss the objective and goals from different perspectives and choose a model accordingly to deliver the expected output.