Rewriting Legacy Applications: When and How to Rebuild from Scratch
Tags: optiontomodernize, legacyapplication, modernizeapplication, legacy
Published: 2023-03-21 16:55:07

In most organizations, legacy applications hold great significance. Nevertheless, they are prone to becoming obsolete, challenging to upkeep, and incompatible with current technologies. Consequently, they may incur exorbitant maintenance costs, have limited functionality, and receive minimal vendor support. 

Organizations may opt to modernize and enhance their legacy applications by rewriting them to address these challenges. This blog post delves into the essential factors organizations should consider when determining whether to rebuild their legacy applications and the various approaches they can take to achieve application rewriting.

## What is Rewriting?

Rewriting an application can be a valuable process as it allows for reevaluating the application approach with the integration of the latest models in development and testing processes. Through this approach, developers can change everything from the programming languages to the frameworks used, providing a chance to correct any mistakes from the previous version. 

Essentially, it is a golden opportunity to refine the application and ensure it meets current standards and requirements.

Rewriting an application offers the chance to reevaluate the development and testing procedures by incorporating the latest models, resulting in a more cohesive approach. Modifying the language and the frameworks used becomes feasible by reworking the application. This presents a valuable opportunity to rectify errors in the previous version, making it a golden opportunity for improvement.

## Why Rewrite Legacy Applications?

Rewriting a legacy application may be necessary for various reasons. The following are some reasons why organizations may consider rebuilding their legacy applications:

### Technology Obsolescence

In today's technological world, the tools and techniques employed to create legacy applications may eventually become outdated. As a result, compatibility issues, security vulnerabilities, and restricted functionality may arise, posing a challenge for businesses. 

To mitigate these concerns, organizations must consider [modernizing legacy applications](https://dev.to/ruchita_varma/why-does-your-business-need-application-modernization-407b) to ensure seamless compatibility with the latest technologies. By doing so, businesses can stay up-to-date with the latest advancements and maintain a competitive edge in the market.

### Business Requirements

Nowadays, organizations need to have the right tools and technologies to stay competitive. However, some organizations still rely on legacy applications designed decades ago, and these applications may need help to keep up with the organization's changing needs. 

For instance, a company may require an application that can scale up or down depending on the demand, works seamlessly on mobile devices, and is cloud-compatible for easy accessibility.

In such cases, rebuilding the legacy application becomes necessary to meet the organization's current needs. While this can be a complex and costly process, the benefits of having an application that meets current requirements outweigh the costs in the long run. By rebuilding legacy applications, organizations can achieve increased efficiency, productivity, and customer satisfaction.

### Technical Debt

As technology advances, older applications can accumulate what's known as technical debt. It's like a sort of "interest" in the cost of maintaining and modifying software systems that have undergone many changes, modifications, and upgrades over time, making them increasingly difficult to maintain. 

In some cases, starting fresh and rebuilding the application entirely is more cost-effective than trying to keep up with the mounting technical debt. This can be a tough decision to make, but sometimes it's necessary to keep your software running smoothly and efficiently.

### Cost

Legacy applications can become costly to maintain over time due to the need for specialized skills, outdated hardware, and software dependencies. By rewriting the application, organizations can reduce maintenance costs and leverage modern technologies that may be more cost-effective in the long run.

### Timeline

Legacy applications can hinder innovation and agility since they might be challenging to modify or integrate with new systems. However, organizations can overcome these obstacles by redeveloping the application. 

This approach can help them streamline development timelines and accelerate the time-to-market for new features and functionality. Furthermore, revamping the application can provide a chance to adopt agile development methodologies, enhancing development speed and effectiveness.

## Which Development Approach to Take?

Choosing the right option for rewriting a legacy application can be challenging for organizations. Let’s compare [Lift and Shift vs. Refactoring vs. Rewriting](https://www.simform.com/blog/lift-and-shift-vs-refactoring-vs-rewriting/) legacy applications.

### Lift and Shift

In the realm of cloud migration, "[lift and shift](https://dev.to/hirendhaduk_/when-to-adopt-lift-and-shift-migration-approach-43m)" has emerged as a viable alternative for businesses seeking to transport their legacy applications quickly and cost-effectively. This method involves transferring applications to the cloud without significantly altering their architecture or codebase. It is an ideal solution for organizations that wish to move their applications with minimal disruption. 

Furthermore, it may be especially beneficial for applications that do not require extensive changes to their existing infrastructure or operational models.

### Refactoring

Refactoring, as a software development practice, can be a viable choice for applications that need gradual, iterative enhancements to boost their functionality, maintainability, and scalability. Refactoring is also a reasonable approach for applications that aren't overly complicated and don't necessitate significant modifications to their overall architecture.

### Rewriting

Rewriting might be the right solution when dealing with applications with technical debt, functionality issues, and architecture problems. Additionally, applications that no longer meet the current needs of an organization and require a complete overhaul may also benefit from a rewrite. In such cases, opting for a complete overhaul through rewriting can be a suitable option to consider.

## Conclusion

As technology advances and businesses evolve, legacy applications can hinder organizational growth. While it may seem daunting, rewriting these applications is often necessary to stay competitive. 

Organizations have several options at their disposal when it comes to rewriting legacy applications, including lift and shift, refactoring, and full-scale rewriting. However, each option comes with its own benefits and drawbacks, and it's important to consider several factors before making a decision.