SDLC (Software Development Life Cycle): What is, Phases & Models

What exactly is the SDLC?
When developing software, the SDLC follows a methodical process to ensure that the software produced is both high-quality and correct. The SDLC process is designed to deliver high-quality software that meets or exceeds customer expectations, among other things. The system development process should be completed within the time frame and budget constraints that have been established. Essentially, the SDLC is a detailed strategy that outlines how to plan, construct, and maintain a specific piece of software. A process and deliverables are associated with each phase of the SDLC life cycle, and these deliverables feed into the next phase. Application Development Life Cycle is another term used to refer to the Software Development Life Cycle (SDLC). SDLC is an abbreviation for Software Development Life Cycle.


The following are the most essential reasons why the SDLC is crucial while designing a software system.
In addition, it serves as a foundation for project planning, scheduling, and estimating.
provides a framework for a defined set of actions and deliverables that are followed
It serves as a tracking and control system for projects.
Increases the visibility of project planning among all stakeholders involved in the development process as a whole.
Development speed has been increased and improved.
Client relationships have been improved.
Reduces project risk and project management plan overhead by utilising this method.
Phases of the SDLC
Every step of the SDLC process is broken down into the following SDLC steps:

SDLC Phases

Phase 1: Identification and analysis of requirements
Phase 2: Feasibility investigation
Phase 3: Conceptualization Phase 4: Coding
Testing is the fifth phase.
Installation and deployment are the sixth and final phases.
Phase 7 is devoted to upkeep.
The phases of the Software Development Life Cycle (SDLC) have been covered in detail in this lesson.

Phase 1: Requirement collection and analysis

This is the first stage of the SDLC process, which is the need. It is overseen by senior team members, who solicit input from all stakeholders as well as domain experts from the industry as a whole. At this stage, the needs for quality assurance are planned, and the risks associated with the project are identified and assessed.

This stage provides a clearer view of the scope of the overall project, as well as the anticipated difficulties, opportunities, and directions that prompted the project in the first instance.

Requirements Teams must collect thorough and specific requirements throughout the gathering step. This assists companies in finalising the necessary timelines for completing the job of the system in question.

Phase 2: Feasibility study

Following the completion of the requirement analysis phase, the next sdlc stage is to identify and document software requirements. The ‘Software Requirement Specification’ paper, also known as the ‘Software Requirement Specification’ document, was used to guide this process. It encompasses everything that has to be conceived and developed during the course of a project’s lifecycle.

There are five types of feasibilities checks that are commonly used:

Economical: Will we be able to execute the project within the budget or will we have to go beyond budget?
Legal: Is it possible for us to conduct this project in accordance with cyber law and other regulatory frameworks/compliances?
Operational feasibility: Are we able to build operations that meet the needs of our clients?
Technical: It is necessary to determine whether the current computer system is capable of supporting the software.
Schedule: Determine whether or not the project can be completed within the time frame that has been set.

Phase 3: Design

It is during this third phase that the system and software design documents are created in accordance with the requirements specification document. This aids in the definition of the overall system architecture.

This design phase provides information that will be used in the following step of the model.

Design documentation of two types are created during this phase: architectural and mechanical.

Design at the highest level (HLD)

Each module is given a brief description and its name.
An overview of the capabilities of each module is provided.
Modules are interconnected through interfaces and are dependent on one another.
Database tables have been discovered, as well as their main features.
Architecture diagrams in their entirety, as well as technological specifications
Design at the Lowest Level (LLD)

The modules’ functional logic is described in detail below.
Tables in a database that give information about the kind and size
Every aspect of the interface is described in detail.
It takes care of all kinds of dependency concerns.
a list of all of the error messages
Every module has a complete set of input and outputs.

Phase 4: Coding

Following the completion of the system design phase, the coding phase will begin. During this phase, developers begin to construct the entire system by writing code in the programming language of their choice. When it comes to the coding phase, duties are broken down into units or modules, and then assigned to different developers. Generally speaking, it is the most time-consuming step of the Software Development Life Cycle process.

During this phase, the developer is required to adhere to a set of predetermined code principles. Furthermore, they must employ programming tools such as compilers, interpreters, and debuggers in order to develop and implement the code.

Phase 6: Installation/Deployment

When the software is finished and has been deployed in the testing environment, it is considered complete. The testing team begins by evaluating the overall functionality of the system. This is done in order to ensure that the entire application operates in accordance with the customer’s specifications.

During this phase, the quality assurance and testing team may discover some faults or defects, which they will report to the developers. The development team corrects the problem and sends it back to QA for a second round of testing. This procedure is repeated until the programme is bug-free, stable, and functioning in accordance with the business requirements of the system in question.

Installation and deployment are the sixth and final phases.
When the software testing step is completed and there are no problems or errors remaining in the system, the final deployment procedure can begin. On the basis of the input provided by the project manager, the final programme is released and tested for deployment difficulties, if any, before being distributed.

Phase 7: Maintenance

Following the deployment of the system and the initial use of the developed system by clients, the following three activities take place.

Bug fixing – bugs are reported as a result of some circumstances that have not been tested in any way at all.
Upgrading the application to newer versions of the software Enhancing the programme by including some new features Enhancing the application by removing some old features
The primary objective of this SDLC phase is to ensure that requirements continue to be met and that the system continues to perform in accordance with the specifications established in the previous phase.

Phase 7: Maintenance

Models of the Software Development Lifecycle that are widely used
Some of the most important models of the Software Development Life Cycle (SDLC) are presented below.

The SDLC follows a waterfall model.
The waterfall model is a frequently used software development lifecycle model. This technique divides the entire software development process into the various phases of the software development life cycle (SDLC). As shown in this SDLC model, the outcome of a phase serves as an input for the subsequent phase.

This SDLC paradigm is heavily reliant on documentation, with early phases recording the tasks that must be completed in the succeeding phases.

Popular SDLC Models

In the SDLC, the incremental model is used.
The incremental model is not a different model from the other models. It is essentially a succession of waterfall cycles repeated over and over. At the outset of the project, the needs are separated into groups for easier organisation. To develop software, the SDLC paradigm is followed by each group individually. Iteratively repeating the SDLC life cycle procedure with each release adding additional functionality until all requirements are met is the goal. Every cycle in this strategy serves as a maintenance phase for the preceding software release, which is called a cycle. The incremental model has been modified to enable for development cycles to be overlapped. After that, a second cycle may begin before the previous cycle has finished. c.

The V-Model in the Software Development Lifecycle
The testing and development phases of this form of SDLC model are planned in simultaneously, which makes it easier to manage. As a result, there are SDLC verification phases on one side of the spectrum and a validation phase on the other. The Coding step is when the V-Model joins.

In the SDLC, the Agile Model is used.
A strategy known as agile approach encourages continuous interaction between development and testing throughout the software development lifecycle (SDLC) of any project. The Agile method divides the entire project into small incremental builds, which are completed one at a time. All of these builds are delivered in iterations, with each iteration lasting somewhere between one and three weeks in length.

Big bang model

The spiral model is a process model that is driven by risk. A waterfall, incremental, waterfall, and other process models are all represented in this SDLC testing model, which assists the team in adopting components of one or more of these models.

This paradigm combines the greatest elements of both the prototyping model and the waterfall model into a single framework. In design and development, the spiral methodology is a combination of rapid prototyping and concurrent activities in the design and development phases.

Model with a big bang
The big bang model is characterised by an emphasis on all forms of resources in software development and coding, with little or no planning. When new requirements are identified, they are understood and executed as soon as possible.

This technique is most effective for short projects with a small development team that is working collaboratively on the project. It can also be used for software development projects in academic settings. It is the best model to use when the requirements are unknown or when the ultimate release date is not specified.


In software development, the Software Development Life Cycle (SDLC) is a systematic procedure for developing product that ensures the quality and correctness of the software produced.
SDLC (Software Development Life Cycle) is an abbreviation for Software Development Life Cycle or Systems Development Life Cycle.
The software development lifecycle (SDLC) provides a framework for a defined set of activities and deliverables in software engineering.
There are seven stages in the SDLC: 1) Requirements collecting and analysis; 2) Design; 3) Development; and 4) Testing. 2) Feasibility investigation: 3) Conceptualization 4) Coding 5) Experimentation: 6) Installation/Deployment and Configuration 7) Upkeep and repair
The requirement analysis step is carried out by the senior team members.
All of the activities that need be designed and developed during the project life cycle are included in the feasibility study stage.
During the Design phase, the system and software design papers are developed in accordance with the requirements specification document.
During the coding phase, developers begin to construct the entire system by creating code in the programming language of their choice.
Testing is the following process, which is carried out to ensure that the complete application operates in accordance with the requirements of the customer.
When the software testing phase is completed and there are no problems or faults remaining in the system, the installation and deployment step begins.
The maintenance face is responsible for bug fixing, upgrade, and engagement activities.
Waterfall, incremental, Agile, V model, Spiral, and Big Bang are some of the most common software development life cycle models (SDLCs) in use today.
A precise plan that describes how to plan, construct, and maintain specific software is known as the software development life cycle (SDLC).