What is the RAD model in Software Engineering?

The software development domain has seen many churns over the years, employing several different models to develop software. Why do you need a model to build software? What is the most used software development model? Which is the best software development model today? Which software development model is being adopted the fastest?

We shall try to answer all these questions in the following sections. A primer on Software Development Life Cycle is in order first.

What is the Software Development Life Cycle (SDLC)?

To engineer something, you need a definite plan and approach to arrive at the product that satisfies the requirements you started with and for the product to fulfill its objectives.

In the distant past, products were innovated with a lot of trial and error. This approach will not work in today’s competitive world. There is a lot at stake for businesses, and a wrong step might result in heavy losses.

In order to keep the process of software development focused on core requirements and be as productive as possible during the entire development cycle, businesses take the approach of well-defined frameworks like various models in the Software Development Life Cycle.

Software Development Life Cycle, as described by Wikipedia, is “a process for planning, creating, testing, and deploying an information system.” Typically, there are six stages involved in this software development life cycle: requirement analysis, system design, coding or development, testing, deployment, and documentation.

There are several models in the software development life cycle, which are:

Waterfall Model

By far the most used and trusted model, this model has been used for a long time now. The model proposes a cascading model to move across the various software development life cycle stages, just like a waterfall. The next stage cannot be started unless the previous stage is complete. This kind of development is also called a linear model of software development.


Another linear model that might not be as popular as the waterfall model is the V-Model of development. The unique characteristic of the V-model is the use of testing at every stage of development. This model helps to detect architecture and code errors quite early but suffers from being expensive and time-consuming.

Incremental and Iterative Model

This modular software design methodology proposes to split the activity of development into several iterations, where new software modules are added in each iteration. This model allows both sequential and parallel development.

Spiral Model

Thorough risk assessment is the theme that the spiral model is based on. The model involves detailed planning, risk analysis, prototype development, and evaluation of the previous stage.

Rational Unified Process

A combination of linear and iterative frameworks, RUP divides the software development process into four stages: inception, elaboration, construction, and transition. Except for inception, all other phases use several iterations. The vital thing to note is that all core development activities like requirements analysis, design, and others are parallel.

Agile Model

The Agile software development model is a more recent development and involves intensive communication, iterative development, and constant customer feedback at its core. The agile development model is the most popular today, with over 70% of the software development businesses using the Agile model.

One such model based on the Agile Model is the Rapid Application Development model. We shall talk about this model in much more detail in the sections below.

Extreme Programming model (XP)

An iterative model at its core, the Extreme Programming model allows changes to be made even after the launch of any iteration. Extreme programming mandates pair programming, test automation and test-based development, continuous integration, and minor but definitive releases.


Kanban stands out from the rest, with the absence of iterative development, keeping it limited to daily sprints, if any. In Kanban, the emphasis is on a visual plan of development.

What is the RAD (Rapid Application Development) model?

The Rapid Application Development model, as the name suggests, is a faster software development model with continuous iterations at its core. It was developed in 1991 by James Martin and is considered a form of Agile software development using quick and short prototype releases over several iterations. The continuous involvement of stakeholders, including the client, is essential in this software development model. Typically, RAD can be applied to projects which can be modularized completely.

There are a few preconditions to the use of RAD for software development.

  • RAD can only be used in projects which allow modularization, and delivery can be done in an incremental fashion
  • RAD needs a heavy investment of time and resources in designing.
  • RAD mandates the use of automated code generation tools
  • RAD also depends heavily on domain experts for approval of prototypes
  • RAD is suggested in scenarios where the development of prototypes is possible in short durations and in situations where there is a high likelihood of changing project requirements during the course of the project.

There are four distinct phases in RAD. Let’s briefly go through each:

Requirements Planning

All stakeholders involved, including users, project managers, and engineering, get together and discuss the business requirements, project scope, development constraints/feasibility, and system requirements. The team has to agree on crucial design aspects before getting approval to continue on the development path.

User Design

Here, the users of the system or the customer interact with system analysts to develop models and prototypes representing the system processes, system inputs and outputs, and flow of information. Various models like business models, data models, process models are prepared and reviewed with the user. Using Joint Application Development and CASE tools, all user requirements are translated into working models. It is a continuous, iterative, and interactive process that allows users to constantly give feedback to improve and develop a system that meets their business requirements.


The construction phase starts to build on the prototypes that the users have approved, but the users continue to provide input in this phase too. They can suggest changes or improvements that they might have missed in the user design phase. This phase involves the actual development of the software using selected application development platforms. The construction phase involves development, unit testing and integration, system testing and integration.


The cutover is the delivery of working software and involves testing, the changeover to the new system, data conversion, user training, etc.


There are well-curated courses and programs, including the Master of Computer Application, available on Great Learning that can help you in understanding more about the RAD model in Engineering and its various applications. The RAD model of software development focuses on building, testing, and delivering, all in consultation with the user to accurately represent the user’s business requirements. Each phase is much more compressed and quicker than traditional SDLC models, thus allowing faster delivery of functional software.