Software Development

Jun 11, 2020

Software Development Life Cycle: SDLC Phases and Models

People want to develop complex things that make our lives more comfortable. Smart homes, or augmented reality abilities made into eye wear. To make these things a reality, companies require designers to design powerful software. They can design every steps of development through software development life cycle.

Software is the essence of complexity. However, no matter how complex, it requires to be flexible, easy to manage, and enhance. How to achieve that? Planning each step of the software development process is a requirement for a successful product. 

Understanding the concept of the software development life cycle (SDLC) is a big kick-off point towards planning any project. This article aims to touch the notion of SDLC, its phases, and methodologies. 

What is a Software Development Life cycle(SDLC)?

The software development life cycle (SDLC) is a process used for structuring the development of any software system, from start through to implementation. This process aims to meet the customer’s demand for fast turnaround, which means low cost, without losing quality.

It consists of a set of tasks required to complete at each stage of the development process. 

Why the Software Development Life Cycle is Important

  • It provides perceptibility for the engaged parties
  • It allows controlling the project
  • Expected deliveries throughout an entire development process
  • Reducing risks like going over budget or deadline breach
  • The process goes on until all the requirements are met

Software Development Life Cycle(SDLC) Phases

Software Development Life Cycle


The very first phase of SDLC is primary planning. The phase includes the aspects of both project management and product management, such as:

  • Scheduling
  • Capacity Planning
  • Material and Human resource allocation
  • Cost Estimation
  • Provisioning

If planning goes successfully, you will get such results as detailed project plans and schedules, cost estimations, and obtainment requirements. 


Business Owners and managers have to cooperate with the IT team to communicate their demands for new development and improvement. 

At the requirements phase, software developers collect requirements from the business owner and experts involved. They work together with the client to document all business processes that the software should automate. 

The three primary activities involved within the analysis phase are as follows:

  • Gathering business requirements
  • Creating process workflows
  • Performing a detailed analysis


After determining requirements, developers and software architects start to design the software. Developers apply discovered software development patterns to solve algorithmic problems. At the end of this phase, teams get design documents with the patterns and components selected for the software, and the code used as a starting point for further development.



This phase is actually about the software under development. Following the defined development methodology, the work can be conducted in:

  • time-boxed Sprints (Agile)
  • A single block of effort (Waterfall) 

The main goal for Software developers, regardless of the picked methodology, is to produce working software as immediately as possible. Business owners should be regularly engaged as well to assure that the software meets their expectations. 

The result of their work is testable and functional software.


This phase is the most important in the software development life cycle, as there is no way to deliver high-quality software without testing. Testers then review the software for errors, bugs, and defects to verify the software’s functionalities work as required or not.

The variety of testing procedures necessary to measure quality includes:

  • Code quality review
  • Unit testing
  • Integration testing
  • Performance testing
  • Security testing

Testers automate these processes to assure that tests are run frequently and never skipped. After completing the phase, full-functional software is ready for deployment.


It’s quite logical to guess that this Phase must require the most attention to detail. However, this phase is highly automated. It can be almost hidden because the software is deployed the moment it is ready. Sometimes manual permissions are also required. The result of this phase is the product release.

Also read about Top Software Development Trends 2020

Software Development Life Cycle(SDLC) Models 

Waterfall Model 

This SDLC model is the oldest and most straightforward. With this system, we finish one phase then start the subsequent. Each phase has its mini-plan and every phase “waterfalls” into the subsequent. The biggest drawback of this model is that tiny details left incomplete can delay the whole process.

Agile Model

SDLC Models

The Agile model separates the product into cycles and delivers a working product very quickly. This methodology produces a succession of releases. Testing of every release feeds back info that’s incorporated into the next version. The disadvantage of this model is that the heavy emphasis on client interaction can lead the project within the wrong way in some cases.

Iterative Model

This SDLC model indicates repetition. Developers build a version very quickly and for comparatively little cost, then test and improve it through rapid and succeeding versions. One big disadvantage here is that it can eat up resources fast if left unchecked.

V-Shaped Model 

An extension of the waterfall model, this SDLC methodology tests at every stage of development. As with the waterfall, this process can run into roadblocks.

Big Bang Model

This high-risk SDLC model throws most of its resources at the development and works best for little projects. It lacks the thorough requirements definition stage of the opposite methods.

Spiral Model

The most flexible of the SDLC models, the spiral model is comparable to the iterative model in its emphasis on repetition. The spiral model goes through the design, design, build, and test phases over and over, with gradual improvements at each pass.