What is rapid application development?

Rapid application development is an approach that focuses on rapid prototyping and feedback for improved flexibility and faster time to market.

As businesses of all kinds face increased expectations in terms of application quality and delivery times, the need for speed and effectiveness in software development cycles has never been greater. But creating effective software quickly is often not enough. Development teams also need the flexibility to adapt to changing app requirements—sometimes mid project. Rapid application development (RAD) may be the answer.

RAD is an adaptive development model that forgoes the rigid structure of traditional Waterfall software development processes in favour of a more agile approach that prioritises speed and flexibility. The result is a development methodology that allows businesses to iterate and incorporate feedback throughout the creative process and into further development.

In other words, RAD places the user firmly at the centre of development, rather than only incorporating their feedback at the start or the conclusion of the process. Through ongoing course correction, rapid application development empowers organisations with the flexibility to more consistently meet user needs while maintaining fast deployment schedules.

Building an effective RAD model requires several distinct stages. Although this process may need to be further broken down to accommodate specific business needs or limitations, the standard stages of RAD include the following:

1. Business modelling

In the first phase of creating an RAD model, organisations must gather relevant business information from a variety of sources. Information flow between business functions is identified and used to create an accurate description of how that data may be applied.

Graphic outlining the phases in rapid application development

2. Data modelling

With the information collected and defined in the previous phase, organisations can now analyse the data and divide it into specific data groups. The relationships between each of these groups are clearly defined.

3. Process modelling

Next, the data objects defined during the data modelling phase are converted for use in the development process. Process modelling allows for changes and optimisations to be made to the data objects.

4. Application development

With the necessary groundwork in place, the organisation can now code the relevant information and build the system. Data models are used to create prototypes which will be tested during the final phase.

5. Testing and turnover

Each model created during the previous stage is individually tested to identify any problems and allow specific components to be adapted quickly to improve the final product. Because the prototypes are tested during each iteration, the total testing time is reduced.

Because rapid application development eschews costly planning and regimented linear models in favour of an approach in which changes can be made during any development stage, it is often grouped together with Agile development. But while RAD incorporates many Agile principles, it is not the same thing.

Agile focuses on breaking projects down into features built during sprints (short periods where a team works to complete a predetermined set of tasks), creating multiple iterations designed to produce feedback as each feature is completed. RAD, on the other hand, places greater focus on prototypes—usable versions of the complete product that can be shared with the user to generate more feedback relevant to the entire app. Rather than waiting for individual features to be completed before seeking user assessment, RAD delivers prototypes still in the development phase so that full functionality may be improved throughout the entire process.

To do this, RAD relies on an extensive repository of reusable code to create and release prototypes quickly, so that the development process remains focused on creating and refining usable software.

Due to its focus on building working prototypes for users to test and evaluate, rapid application development brings with it several advantages over other software development methodologies. These benefits include:

  • Development can easily pivot to accommodate changing project requirements.
  • Release versions can be produced quickly without the need to create or plan for large development cycles—RAD tools help speed the process.
  • Progress between prototypes is easy to track and measure.
  • Reusable code reduces the likelihood of errors and cuts down on the necessary testing times.
  • Reducing time to market and eliminating the possibility of needing to rerun projects, RAD allows development teams to accomplish more at lower cost.
  • Customer feedback is encouraged as the primary testing method, improving user involvement to achieve a more effective product.
  • Risks may be discovered and addressed early in the process, rather than being put on hold until the definitive version of the software is nearing completion.
  • Software integrations are built into the application throughout the development process, ensuring that the final product is capable of functioning optimally with other tools and systems.
  • New technologies may be incorporated as they emerge—even mid-development.
  • Versions may be released quickly and without significant effort, reducing the time to market of essential applications.

Despite its many benefits, there are some disadvantages to be aware of when considering the RAD model. These may include:

  • RAD depends heavily on highly trained and experienced team members to identify business requirements and create working models.
  • Larger teams or projects with too many stakeholders may be incapable of collaborating effectively or embracing the flexibility needed for rapid application development.
  • RAD is only appropriate for systems that can be effectively modularised.
  • User requirements must be clearly defined throughout the project lifecycle.
  • The high cost of modelling and automated code generation can make RAD prohibitively expensive when applied to lower-budget projects.
  • RAD is best suited to projects that require shorter development times; long-term projects may benefit from other methodologies.

With the above disadvantages in mind, it’s clear that rapid application development is best suited for projects that have a large and responsive pool of users that are committed to testing the application and providing detailed feedback. At the same time, organisations need teams of highly skilled and motivated developers to quickly fulfil requested changes to ensure that new prototypes are being rolled out quickly. Projects or scenarios that fall outside of these requirements may be poorly suited for rapid application development.

To ensure effective RAD results, consider the following best practices:

  • Make sure that there is enough budget to cover costs, particularly those associated with automated code generation tools.
  • Have available domain experts on hand to provide the necessary business knowledge.
  • Apply RAD only to projects that can be easily broken down into specific modules; those that cannot be modularised may not benefit from RAD.
  • Consider RAD for projects with non-static requirements to address changing needs smoothly via prototypes presented directly to users on a regular basis.
Rapid application development can be a major advantage when applied to the right projects, but it does carry with it certain limitations. Thankfully, many of those limitations may be mitigated with the right tools.

The ServiceNow App Engine supports Rapid Application Development, enhancing developer capabilities and applying essential workflow automation. APP Engine delivers full-stack development capabilities and application structure out of the box and is fully capable of integrating with virtually any third party or external system. The end result? You enjoy the capabilities you need to build powerful apps, and to refine them as you go.

Experience the benefits of fast application development and deployment; learn more about App Engine, and revolutionise the way you create the apps that drive your business.

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