SDLC (Software Development Life Cycle): Phases, Models

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The Software Development Life Cycle (SDLC) is a methodology for producing high-quality software with clearly defined processes. This article will outline the SDLC process, explore each phase in greater detail, and give examples to help you comprehend each step.

What is software development lifecycle and why is it important?

The Software Development Life Cycle (SDLC) is a structured procedure that allows the most efficient and fast development of high-quality, low-cost software. The objective of the SDLC is to create great software that meets and surpasses all requirements and expectations of the stakeholders and end-customers.

Thanks to SDLC the requirements can be analyzed by developers working on the project. During development, it aids in cutting back on unnecessary expenses. The early stages of SDLC allow developers to calculate costs, foresee potential costly issues and other blockers. Such approach directly transfers to creating better digital products.  

Where is system development life cycle used?

The software industry uses the Software Development Life Cycle (SDLC) method to plan, create, and test high-quality software. The goal of the SDLC is to develop high-quality software that meets or exceeds customer expectations while finishing on schedule and under budget.

The system development life cycle is a project management framework that outlines the steps necessary to take a project from a concept to completion. For instance, teams working on software development use a range of system development life cycle models, such as waterfall, spiral, and agile methods, which we’ll try to briefly explain in this article. 

Why is security important in SDLC?

SDLC process consists of a thorough plan outlining the development, upkeep, replacement, and modification or improvement of particular software. The life cycle defines a methodology for enhancing software quality,including it’s security, and the overall development process.

Coding with potential vulnerabilities in mind is crucial in SDLC, because anyone could theoretically get access to the source code and use it for malicious purpose. Having a solid and secure SDLC process is essential to ensure that your application is safe from attacks and exploits. 

Main stages of software development process

The Software Development Life Cycle (SDLC) is a set of critical stages that teams must follow in order to produce and deliver high-quality software.

Analyzing & Planning

The most fundamental stage in the SDLC process, where a business analyst, domain expert, and project manager all work together to gather and evaluate business needs. Stakeholders and  business analyst working together, prepare the business requirements document. In addition, they document use cases and provide the project team with necessary data.

The requirements analysis aims to identify potential risks to be addressed to ensure software success, as well as to provide quality assurance and technological viability.


The stage where lead developers and technical architects construct the initial high-level design strategy for the software and system throughout the design phase. This includes the delivery of requirements used to create the Design Document Specification (DDS). The document details database tables to be added, new transactions to be defined, security processes, as well as hardware and system requirements.  


This stage is crucial for developers. During the phase, the database administrator creates and imports the necessery data into the database. Previously prepared requirements define the languages used in programming. The interface is built by developers who perform unit testing according to the coding standards. They must be adaptable and open-minded if the business analyst makes any modifications. 


Testers compare the software to the requirements to ensure that the software meets the needs identified and addressed during the planning phase. Unit tests, integration tests, system tests, acceptance tests, and non-functional tests are all performed as functional tests. 


The customer receives the product once it has undergone testing and quality assurance. Deployment engineers typically work on this step, making software accessible to clients. They might help a business install the program, or one-on-one clients use the program on their devices. 

Maintenance stage

The system is in maintenance mode in a live software environment for post-production. Issues will arise regardless of the software’s complexity, user base, or despite rigorous QA testing. That’s simply how the software development life cycle worksRegular maintenance and staying up to date on upgrades are equally important, as having access to knowledgeable, trustworthy support resources. 

What are the SDLC models/methodologies?

The term “Software Development Life Cycle” refers to a methodology for producing high-quality software that includes well-defined processes. Also known as SDLC, it is a method for creating software that is of the highest quality and least expensive in the shortest amount of time. The well-organized phases of the SDLC allow an organization to swiftly develop high-quality software that is well-tested and prepared for usage in production.

The SDLC approach includes the following phases; analysis of requirements, planning, software design, development, testing, and software deployment.

software development lifecycle

Waterfall Model

The waterfall model is a linear, sequential approach to the software development lifecycle (SDLC) widely used in software engineering and product development. 

The waterfall model follows a logical succession of SDLC processes for a project, much like the way water pours over a cliff’s brink. For every stage of development, it establishes clear endpoints or objectives and once certain endpoints or objectives have been accomplished, they cannot be revisited. It is frequently referred to be the first software development technique still used by applications for industrial design, as a high-level project management methodology for challenging, diverse undertakings. 

Agile Model

Instead of a top-down procedure with a single set of steps, the Agile SDLC development technique emphasizes collaborative decision-making, customer satisfaction, and development over a number of brief cycles or sprints. Software development teams operate in various cycles, each lasting two to four weeks. Instead of proceedingaccording to plan,” developers utilize an iterative method to concentrate on the most crucial elements at any given time. 

Iterative Model

In the iterative model, the process iteratively improves the evolving versions until the entire system is implemented and prepared for deployment. It begins with a simple implementation of a limited set of software requirements. Only a portion of the software is specified and implemented in the beginning, and then it is reviewed to find any additional requirements for futher improvement. After each iteration of the model, this process is repeated to create a new version of the software. 

V-Shaped Model

The V-model or and Validation model, is a particular SDLC model where processes run sequentially in a V-shape. Its foundation is the correlation of a testing phase with each relevant development step. Each step’s creation is directly related to the testing phase and only after the previous stage has been completed the next phase begins. 

Lean Model

Lean Software Development is an agile framework that optimizes development time and resources, eliminates waste, and ultimately delivers only what the product needs. The Lean approach is also often referred to as the Minimum Viable Product (MVP) strategy, in which a team releases a bare-minimum version of its product to the market, learns from users what they like, don’t like, and want to be added, and then iterates based on this feedback. 

Spiral model

The well-known spiral model, also known as the waterfall model, which places tremendous emphasis on risk analysis, combines the iterative development approach and the sequential improvement model. According to this approach, the precise number of product development phases changes depending on various restrictions and the project manager’s ability to estimate project risks. The project manager makes a number of stage decisions on the fly and so has a significant impact on how a product develops utilizing the spiral model.

The spiral’s radius typically represents the costs or sums required for project development. The angular dimension displays the progress made during the most recent phase. 


Management and development techniques serve as a framework for software development process. They also give each member of the team a clearly laid out plan so that everyone is aware of what they are doing, why they are doing it, and what the end result is. As the SDLC evolved, various models were developed to satisfy a wide range of development expectations and requirements. Instead of excessive regularity and orderliness, the world is moving toward flexibility today thus Agile model is the most popular today as it perfectly meshes responsiveness and well-organized project management. 

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Which phase of the SDLC gathers business requirements?

Project goals and business requirements are gathered and turned into precise functions in the analysis phase.

In which phase of the SDLC is the project plan developed?

The project plan, which identifies, prioritizes, and assigns the tasks and resources needed to build the structure for a project, is developed during the planning phase of the SDLC. This stage results in a thorough project plan.

Which SDLC phase is performed with both internal software development and outsourcing?

Due to the need for end-user involvement, internal software development and outsourcing can be used to complete the testing and the first SDLC stages.

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