What is SDLC?
The term “SDLC” refers to the Software Development Life Cycle. Software Development life cycle is a process used by software industry to design, develop and test software’s. To put it simply, it is a roadmap or framework that directs the development of software from conception to retirement. In order to prevent confusion in the middle of the process, it helps standardize and structure it.
Technically speaking, the Software Development Life Cycle (SDLC) divides software development into stages so that each can be planned, overseen, and evaluated. Reducing risks, maintaining stakeholder alignment, and making sure the finished product lives up to expectations are the objectives. +1 Amazon Web Services, Inc.
Comparable to building a house, it requires planning, foundation laying, wall construction, wiring installation, inspection, and maintenance. That software development life cycle is called SDLC.
Why is SDLC Important?
Managing software development can be difficult because of evolving requirements, technological advancements, and cross-functional cooperation. At each step of the software development process, the software development lifecycle (SDLC) methodology offers a methodical management framework with defined deliverables. As a result, everyone involved in software development has a plan to accomplish the goals and requirements that have been agreed upon up front.
- Clarity and mutual comprehension
Confusion is reduced when developers, testers, business analysts, and stakeholders all adhere to the same phases. Everyone is aware of what to anticipate. - Improved estimation and planning
Knowing your phases and deliverables in advance allows you to make more accurate time, cost, and resource estimates. - Reduced risk and rework
You frequently have to go back and take action if you neglect requirements or planning. Early validation is encouraged by SDLC, which helps identify errors before they become serious. - Accountability and quality assurance
To prevent flaws from building up undetected, you can implement quality gates, reviews, and verifications at every stage. - Scalability and maintenance
Software must be maintained, updated, or retired once it goes live. The structure of the SDLC aids in the management of these post-release stages as well.
In summary, the SDLC serves as the foundation for teams to effectively manage complexity, produce work with consistency, and stay ahead of the curve.
How Does SDLC Work?
Let’s get started and examine the moving components. Although the names and number of phases of an SDLC can vary depending on the model, a typical SDLC operates as follows (with some real-world disclaimers):
- Requirements / Analysis
Stakeholders are consulted, functional and nonfunctional requirements are gathered, specifications, user stories, etc. are created here. This is usually the most difficult stage, in my experience, because stakeholders change their minds. - Design
Convert requirements into detailed and architectural designs, including components, interfaces, data models, system architecture, and UI/UX design. - Development / Implementation
Coding is the process of creating modules, parts, and integrating them. Code is written and committed by developers. This occurs in iterations in agile models. - Testing / Verification
QA and testers verify that the software satisfies requirements, sometimes using automated tests. You conduct system, acceptance, integration, and unit tests. - Deployment / Release
The software is deployed to the production environment and goes live. Sometimes fully implemented, sometimes in stages. - Maintenance / Support
Bug fixes, updates, new features, and optimizations will be made after the product is released. You may eventually switch to new systems or retire certain components.
Some models collapse or reorder these phases in practice. However, the main concept is: a flow from idea → requirements → design → build → test → deploy → maintain.
Additionally, the SDLC is not always linear. Depending on methodology, many contemporary models run in parallel, loop back, or overlap phases (more on that soon).
What Are SDLC Models?
Things start to get interesting at this point. Your SDLC’s flexibility or rigidity depends on the model you choose. Here are a few popular ones, along with their benefits and drawbacks and potential applications.
1. Big Bang Model
The Big Bang Model is one of the simplest SDLC approaches. Under this model, developers don’t do much planning or requirement analysis before they begin coding. Everything is constructed rapidly, and as concepts develop, adjustments are made.
It works best for academic prototypes, small projects, or situations where requirements are not clear from the outset.
Example –
- Microsoft Word / Office: Modern versions with AI grammar checks, cloud storage, and real-time collaboration replaced the initial versions with more basic features.
- Student or Startup Projects: This model is frequently used to rapidly test concepts and create a Minimum Viable Product (MVP).
Pros: Development can be started quickly and easily, and it is flexible enough to be changed at any time.
Cons: Lack of structure and high risk inadequate scalability and documentation, challenging to administer in intricate or sizable systems.
2. RAD Model
The RAD Model focuses on speed, prototyping, and user feedback. RAD places more emphasis on rapidly creating working prototypes and improving them in response to ongoing user feedback than it does on lengthy planning stages.
It’s perfect if you want active user involvement during development and need software delivered quickly.
Example –
- Online Banking Systems: Interfaces are quickly developed and tested based on user input to enhance features like security and transaction flow.
- CRM Applications (like Salesforce): Modules are rapidly developed and continuously improved to meet user requirements.
Pros: Quicker development and earlier delivery.
Cons: Requires developers with a high level of skill.
3. Prototype Model
Prototype is a blueprint ( dummy product ) of the Software.
Initial requirements from the customer -> Design -> Prototype -> Customer Evaluation -> Refined Prototype -> Final Product->Testing & Implementation
Using the Prototype Model, an SDLC technique, developers create a working mock-up, or prototype, of the system early in the process. This prototype gives users a better idea of how the final system will look and function, allowing them to suggest improvements before full development begins.
This model is effective when requirements are unclear or constantly evolving.
Examples
- E-commerce Websites: Before the final site is launched, early layout and shopping flow prototypes are tested.
- Mobile Applications (like Swiggy or Zomato): Users are given access to clickable UI mockups to improve the features and navigation of the app.
Pros: Users can test and provide feedback early on, and early visualization aids in the collection of precise requirements.
Cons: May lead to irrational expectations if consumers mistake the prototype for the finished product.
4. Iterative / Incremental Model
The Iterative Model in the Software Development Life Cycle (SDLC) is an approach where the development process is divided into smaller, manageable iterations or cycles. Each iteration produces a working version of the software, with enhanced features and functionalities, and goes through phases like planning, design, coding, testing, and review.
The Incremental Model in the Software Development Life Cycle (SDLC) is a method where the software is designed, implemented, and tested incrementally, meaning that the project is divided into smaller modules or parts. Each part (or increment) adds new functionality to the system and builds on the previous increments until the complete system is fully developed.
You build the system in small components and iterate, test, and refine it rather than finishing it all at once. Each iteration may go through multiple SDLC phases, but only for a portion of the functionality.
Example –
- Microsoft Word / Office – While the earlier releases were more basic, each new version iteratively added features like real-time collaboration, cloud sync, and AI grammar checks.
- ERP Systems (SAP or Oracle) – These, like the finance module, HR module, and supply chain module, are released in stages.
Pros: You get early working increments and are flexible and adaptive.
Cons: Scope creep and management overhead for multiple iterations are risks.
5. Spiral Model
The Spiral Model in Software Development Life Cycle (SDLC) is a risk-driven process model that combines iterative development with systematic risk management. It was introduced by Barry Boehm in 1986 and is suitable for large, complex, and high-risk projects. The Spiral Model allows for incremental releases of the product or incremental refinement through each iteration, or “spiral.”
Spiral model is one of the most important Software Development Life Cycle models, which provides support for Risk Handling. In its diagrammatic representation, it looks like a spiral with many loops.
It provides a systematic and iterative approach to software development.
It is a risk-driven model, meaning that the focus is on managing risk through multiple iterations of the software development process.
In every cycle we do follow SDLC process.
- Boeing 787 Flight Software – Developed in cycles, each addressing design risk, safety analysis, and performance testing.
- Defense or Government Projects (like ISRO Mission Control Software) – Follows spiral approach to evaluate risk and technology feasibility in each phase.
Pros: Explicit risk management is beneficial for big, intricate projects.
Cons: Not suitable for small projects; can be costly.
6. Waterfall Model
The Waterfall Model is one of the oldest and most traditional Software Development Life Cycle (SDLC) models. It is a sequential design process, meaning that development flows steadily downwards through distinct phases, like a waterfall.
It’s the traditional, sequential, one-phase model. You proceed to the next phase after the completion of the previous one. Don’t overlap.
Example –
The Waterfall model works well for NASA’s Spacecraft Software Projects because the code cannot be readily altered once it is in orbit and requirements must be exact and stable.
Pros: Easy to comprehend, manage, and good if requirements are well-established and consistent.
Cons: Stiff. It hurts if a change is required at the last minute. does not effectively manage volatile requirements. Wikipedia
7. V-Model (Validation & Verification)
The V-Model in Software Development Life Cycle (SDLC) is an extension of the traditional Waterfall Model, where development and testing are planned in parallel. It emphasizes a highly structured, verification and validation approach to software development. The “V” in the V-Model represents the process’s shape: as you move down the left side of the “V,” the focus is on defining requirements and designing the system, while the right side focuses on testing and validation.
A waterfall variant in which every stage of development is accompanied by testing. Early on, you create tests that match the requirements and design stages.
Example –
- Medical Device Software (e.g., Philips Healthcare) – Every feature needs to be validated in accordance with medical standards (FDA, ISO 13485).
- Automotive Embedded Systems (like ABS software in BMW or Tesla) – Design requirements are directly mapped to safety and validation testing.
Pros: Early test planning and strong traceability between design and tests.
Cons: Less adaptable to mid-project modifications, still inflexible.
8. Agile / Scrum / DevOps (and Variants)
The Agile Model in the Software Development Life Cycle (SDLC) is a flexible, iterative approach to software development that focuses on continuous improvement, customer feedback, and adaptive planning. Unlike traditional models like the Waterfall or V-Model, Agile breaks down the entire project into small, manageable sections called iterations or sprints, allowing for regular delivery of working software and the ability to make changes quickly based on feedback.
Agile Model / Agile Methodology / Agile Process
It is an iterative and incremental approach.
It is an iterative and incremental process.
These are iteration-based, collaborative, and more adaptable. Agile divides development into feedback loops and sprints. DevOps blurs the boundaries between development and operations by emphasizing automation, continuous integration, and continuous delivery (CI/CD).
Examples :
- Spotify’s Agile Squads: With an emphasis on quick releases, each team works on specific features (like playlists or suggestions) in short sprints.
- Updates to the Zomato and Swiggy apps : As is common with agile sprints, these companies release these often in response to user feedback.
Pros: Close cooperation, regular value delivery, and high adaptability.
Cons: Needs discipline; if poorly managed, can become chaotic; documentation may suffer.
How Does SDLC Compare with Other Lifecycle / Management Methodologies?
SDLC is often compared with broader or different lifecycle frameworks. Find below few comparisons.
SDLC vs ALM (Application Lifecycle Management)
The SDLC focuses on how a particular software application is developed, maintained, and retired. ALM is more all-encompassing; it includes a range of applications such as change management, governance, portfolio management, and collaboration.
SDLC vs Project Management Lifecycles (e.g. PMBOK, PRINCE2)
Project lifecycles concentrate on stages that deal with managing resources, time, and money, such as initiation, planning, execution, monitoring, and closure. The technical development of software work is the focus of the SDLC. The SDLC and the project lifecycle frequently overlap.
SDLC vs ITIL / Service Lifecycle
ITIL encompasses incident management, operations, support, service delivery, and change management. SDLC is concerned with the creation and development of software, whereas ITIL concentrates on the operation and upkeep of software as a service. They complement each other.
SDLC vs Business Process Lifecycle
Business process cycles address workflows, processes, and business optimization. The SDLC is technically focused and unique to software artifacts.
Hybrid / Agile vs Traditional Models
Traditional models like waterfall and V are more rigid and sequential, whereas modern models like agile and DevOps emphasize continuous delivery and adaptation. Although the SDLC provides a general framework, the “model” you select will determine how flexible or rigid the lifecycle is. A lot of teams employ hybrid approaches, which blend aspects of agile and lean waterfall.
The Software Development Life Cycle (SDLC) is a software-centric methodology that generally enhances project, operational, or governance lifecycles rather than conflicts with them.
FAQs
Q1: Is the Software Development Life Cycle (SDLC) required for all software projects?
A: Not in a strict sense. Ad hoc work may be done on very small or disposable scripts. However, SDLC (or a variation of it) helps prevent confusion, rework, and chaos for any large project.
Q2: What is the “best” SDLC model?
A: one-size-fits-all solution does not exist. “Best” is dependent on a number of factors, including stakeholder involvement, team maturity, risk tolerance, project complexity, and requirement stability. Agile/iterative methods typically prevail for projects that are unpredictable.
Q3: When in the SDLC should security be implemented?
A: Right from the start. “Shifting left” refers to integrating security procedures into all stages, not just final testing. That is what a Secure SDLC (SSDLC) is all about.
Q4: Is it possible to combine various SDLC models?
A: In agreement. A lot of systems in the real world are hybrids. For core infrastructure, you might use waterfall, but for front-end modules, etc., you might use agile.
Q5: What is the relationship between DevOps and SDLC?
A: By combining development, operations, automation, feedback loops, and continuous delivery, DevOps can be viewed as an advancement of the SDLC. Instead of rigid phase boundaries, it frequently suggests a more flexible, overlapping lifecycle.
Conclusion
When I think back on that first day of being given code to test, I realize that I was lacking context, structure, and procedure. SDLC provides that context. It does not ensure perfection, but it does offer direction, reduce blind spots, and ease the journey.
If the SDLC is viewed as a living scaffold rather than a rigid box, it can be a strong ally rather than a constraint. This includes phases of customization, security fold-in, and adaptation.
If you liked this tutorial and would like more detailed information on subjects like Agile SDLC or implementing secure SDLC in cloud environments, I’d be happy to help you further. Tell me what you wish to do!
Refer below link for deeper reading :
- For deeper reading on SDLC and security: [Red Hat on security in SDLC] (external) Red Hat
- For methodology comparisons: [LegitSecurity: SDLC Models] (external) Legit Security
Hope this helps you build an impressive, human-feeling, SEO-friendly blog on SDLC. If you’d like me to refine certain sections (or simplify further), just tell me!