The Complete Guide to Rearchitecting Applications for the Cloud: Benefits and Best Practices

When your application struggles to keep pace with the growing demands of your business, finding the most effective rearchitecting strategy becomes critical. Rearchitecting and moving to the cloud often presents a promising solution, but it also raises several key considerations:

• Is rearchitecting your application for the cloud the right path to achieve your business goals?
• What business outcomes can you expect by adopting cloud-based architectures?
• What are the different approaches for cloud rearchitecting, and how do you choose the most suitable one?
• How do you select a trusted company to guide you through the cloud rearchitecting process?

This article addresses these essential questions and offers a roadmap for confidently transforming your legacy systems into modern cloud-native applications. Drawing from over a decade of experience in cloud architecture and application modernization services, we’ll provide practical insights from our team, along with real-world examples of successful product rearchitecting cases.

What is application rearchitecting?

In simple words, rearchitecting is the process of redesigning the underlying architecture of an existing application to improve its performance, scalability, and maintainability. This approach often involves breaking down a monolithic system into more manageable components, such as microservices, or migrating the application to a more modern platform or cloud environment. 

Rearchitecting is usually undertaken when the existing architecture no longer meets the business’s evolving needs or hinders further product development and innovation. The goal here is to create a more flexible and robust system that can better support current and future business requirements.

Reasons to rearchitect legacy applications 

Rearchitecting legacy applications offers several key benefits that can significantly enhance an organization’s technology infrastructure and overall business operations:

1. Improved scalability. By redesigning the application’s architecture, organizations can ensure that their systems can scale more easily to accommodate increased demand and meet current business needs. This is particularly important for businesses experiencing growth or fluctuating workloads.
2. Enhanced performance. Rearchitecting often involves optimizing the application’s components and processes, leading to faster response times and more efficient resource utilization. This results in a more responsive and reliable system that meets user expectations.
3. Better flexibility. A rearchitected application is typically more modular and adaptable, allowing for easier updates, integration of new features, and quick adaptation to changing business needs. This agility enables organizations to respond faster to market changes and opportunities.
4. Cost efficiency. Modernizing the architecture can reduce long-term operational costs by streamlining processes, reducing maintenance efforts, and optimizing resource usage. Additionally, it can lower the costs associated with legacy infrastructure, such as outdated hardware or software licenses.
5. Optimized security. Legacy systems often have outdated security measures, making them vulnerable to threats. Rearchitecting allows organizations to implement modern security protocols, ensuring better protection of sensitive data and compliance with industry regulations.
6. Better integration capabilities. Rearchitected applications are usually designed with modern integration standards, making connecting with other systems, applications, or cloud services easier. This enhances the overall functionality and value of the application within the organization’s ecosystem.
7. Future-proofing. Rearchitecting positions the application for future technological advancements, ensuring that it remains relevant and capable of leveraging emerging technologies such as artificial intelligence, and machine learning.
8. Compliance and regulatory alignment. Rearchitecting provides an opportunity to align the application with current compliance standards and regulatory requirements, reducing the risk of legal issues and ensuring that the organization meets industry best practices.

When you should consider application rearchitecting

Application rearchitecting requires significant efforts, and it should be considered under specific circumstances where the existing architecture no longer meets your needs. Here are key scenarios when you should consider rearchitecting an application: 

1. Outdated technology stack. If your application relies on outdated or unsupported technologies, it can be challenging to maintain, secure, and scale. Rearchitecting allows you to transition to modern technologies that offer better performance, security, and compatibility with current standards.
2. Scalability issues. As your business grows, your application may struggle to handle increased workloads, resulting in slow performance or downtime. Rearchitecting can help you redesign the application to scale more efficiently, accommodating higher traffic and user demand without compromising performance.
3. Integration challenges. If your application needs to integrate with newer systems, cloud services, or APIs but struggles due to its current architecture, rearchitecting can help. By modernizing the architecture, you can improve interoperability and ensure smoother integration with other platforms and services.
4. Security vulnerabilities. Legacy applications may have outdated security measures, making them susceptible to cyber threats. Rearchitecting provides an opportunity to build in reliable security features that protect against current and emerging threats.
5. Inflexibility to business changes. If your application cannot easily adapt to new business requirements or changes in the market, it may be holding your organization back. Rearchitecting allows you to create a more flexible and adaptable system that can evolve with your business. Rearchitecting also helps future-proof your application, ensuring it can handle new features, higher user loads, and other growth-related demands.
6. Regulatory compliance. When new regulations or compliance standards arise, your legacy application may not meet these requirements due to architecture limitations. Rearchitecting enables you to incorporate necessary compliance measures, reducing the risk of legal issues.
7. End-of-life systems. When components of your application or its underlying infrastructure are reaching their end-of-life (EOL), rearchitecting may be necessary to replace these components with modern alternatives that are supported and more efficient.

Overall, application rearchitecting should be considered when your existing system is limiting your organization’s ability to grow, innovate, or meet new challenges and simpler application modernization techniques are not enough to change this. By proactively rearchitecting, you can position your application — and your business — for the long-term span of life.

Comparing rearchitecting with other modernization approaches 

When considering application modernization, it’s important to understand the differences between rearchitecting, application refactoring, and application replatforming, as each approach serves different purposes and involves varying levels of complexity and transformation. Here’s a comparison of rearchitecting with these other approaches:

Rearchitecting vs. Refactoring

Rearchitecting involves a fundamental overhaul of an application’s architecture to improve its scalability, performance, security, and adaptability. This process often includes redesigning the system’s components, integrating new technologies, and potentially moving to a new infrastructure or architectural style (for example, transitioning from a monolithic to a microservices architecture).

Key Points:

• Scope: Rearchitecting is broader and more invasive than refactoring, as it involves changing the core structure of the application.
• Purpose: It is typically pursued to address significant limitations in scalability, flexibility, or technology compatibility.
• Impact: The changes made during rearchitecting can lead to a completely different system in terms of architecture and functionality.

Refactoring, on the other hand, involves improving the internal structure of the existing codebase without altering its external behavior. The goal is to enhance code quality, make it easier to maintain, and reduce technical debt. Refactoring is usually an incremental process that focuses on optimizing code for better performance, readability, and future development.

Key Points:

• Scope: Refactoring is more targeted and less disruptive than rearchitecting, focusing on code-level improvements rather than system-wide changes.
• Purpose: It is often done to improve code quality, reduce complexity, and enhance maintainability without changing the system’s overall architecture.
• Impact: The application’s functionality remains the same, but the codebase becomes cleaner and more efficient.

Rearchitecting vs. Replatforming

Replatforming involves moving an application from one platform to another with minimal changes to the underlying codebase. This process often includes migrating from on-premises infrastructure to a cloud platform or moving to a more modern operating system or database.

Key Points:

• Scope: Replatforming is less invasive than rearchitecting, as it focuses on platform migration rather than redesigning the application’s architecture.
• Purpose: It is usually pursued to leverage the benefits of a new platform, such as cost savings, improved performance, or access to cloud services, without altering the application’s functionality.
• Impact: The application operates similarly to how it did before, but on a new platform that may offer better performance, scalability, or cost efficiency.

Rearchitecting is a broader and more complex approach that changes the entire architecture of the application while refactoring focuses on improving the existing code without altering the application’s external behavior.

Rearchitecting involves a deep redesign of the application’s architecture to address fundamental issues and prepare for future growth, whereas replatforming focuses on migrating the application to a new platform with minimal changes to its codebase. 

Choosing between these approaches depends on the specific challenges and goals of your application modernization project. Rearchitecting is typically pursued when an application needs a significant transformation while refactoring and replatforming are more suitable for gradual improvements or platform migrations.

To summarize this section, take a look at the table below.

App rearchitecting process: a step-by-step process

The app rearchitecting process is a complex, multi-step approach that involves thoroughly analyzing, redesigning, and rebuilding an application to meet modern requirements. Below is a general step-by-step guide to the app rearchitecting process:

1. Audit and planning

Auditing and planning for modernization is a critical first step in rearchitecting an application. This phase ensures that the modernization efforts are aligned with business goals, technical requirements, and user needs. During this step, it’s necessary: 

• Thoroughly analyze the existing architecture of the application. This includes identifying dependencies, technologies used, data flow, integration points, and performance bottlenecks. 
• Align the rearchitecting process with the organization’s strategic goals. Define the desired outcomes, such as scalability, flexibility, or reduced operational costs.
• Determine the possible level of remaining technical debt, including outdated code, inefficient processes, and architecture limitations. Prioritize areas that need improvement.
• Conduct a feasibility study to determine the potential risks, costs, and benefits of rearchitecting. This helps in deciding whether to proceed with rearchitecting or consider alternative modernization approaches.
• Develop a detailed plan outlining the scope, timelines, resources, and milestones for the rearchitecting process.

2. Architecture redesign

This step involves rearchitecturing planning in terms of choosing the approach and strategy for data management. During this step, it’s necessary to: 

• Choose a suitable architecture that aligns with the business goals. Common choices include event-driven architectures, serverless architectures, monolithic architectures, and microservices in combination with other elements. 
• Analyze the data flow to check for any gaps and ensure everything is fine (for some cases, consider the implementation of the CAP theorem). Redesign the data architecture to support the new application architecture. This may involve migrating to a new database system, implementing data partitioning, or optimizing data retrieval methods.
• Select the appropriate technologies, tools, and platforms that best fit the new architecture. This might include choosing a cloud provider, database technologies, middleware, or development frameworks.

3. Development and implementation

The development and implementation stage of architecture redesign is where the planned architecture is brought to life through coding, integration, testing, and deployment. This stage turns the architectural design into a functioning system that meets the identified requirements. During this step, it’s necessary to: 

• Refactor the existing codebase where necessary to fit into the new architecture. This might involve rewriting significant portions of code, changing how data is accessed, or reworking business logic.
• Develop new components or services as per the redesigned architecture. Ensure these components are modular, scalable, and easily maintainable.
• Integrate the new architecture with existing systems or third-party services. Use APIs, or integration platforms to ensure seamless communication between components.
• Conduct testing at various levels (unit, integration, system, and user acceptance testing) to ensure that the new architecture functions correctly and meets performance, security, and reliability standards.
• Improve the application’s performance by optimizing resource usage, load balancing, and ensuring that the application can scale to meet user demand.

4. Migration and deployment

This is where the new architecture is transitioned from development to a live environment. This phase ensures that data and users are seamlessly moved to the new system with minimal disruption. During this step, it’s necessary to:

• Migrate existing data to the new architecture, ensuring data integrity and minimizing downtime. This might involve data transformation, replication, or synchronization techniques.
• Develop a deployment strategy that includes deployment pipelines, continuous integration/continuous deployment (CI/CD), and rollback plans in case of issues.
• Consider a phased or parallel deployment where the new architecture is rolled out incrementally. This reduces risks and allows for continuous monitoring and adjustment.
• Implement monitoring and logging tools to track the performance and health of the application in the new architecture. This ensures that any issues can be quickly identified and resolved.

5. Post-deployment review and optimization

Post-deployment review and optimization involve evaluating the rearchitected system’s performance, identifying improvement areas, and refining the architecture to enhance efficiency, scalability, and harmony with business goals. During this step, it’s necessary: 

• Continuously monitor the application post-deployment to ensure it meets the expected performance benchmarks. Analyze metrics such as response time, throughput, and error rates.
• Gather feedback from users to identify any usability issues or feature gaps in the rearchitected application.
• Based on the monitoring data and user feedback, make necessary adjustments to optimize the application’s performance, security, and user experience.
• Document the new architecture, including the rationale for architectural decisions, data flows, and component interactions. This documentation is essential for future maintenance and scaling.

6. Training and knowledge transfer

This phase ensures that all stakeholders, including developers, operations teams, support staff, and end-users, are well-prepared to work with the new architecture. This is essential for the successful adoption and ongoing maintenance of the system. During this step, it’s necessary to:

• Provide training to the development, operations, and support teams to ensure they are familiar with the new architecture and technologies.
• Facilitate knowledge transfer sessions to ensure that all stakeholders understand the new architecture, including its benefits, limitations, and maintenance needs.

7. Continuous improvement

This stage is focused on the ongoing optimization and enhancement of the new architecture after it has been deployed. This phase ensures that the system remains efficient, secure, and aligned with evolving business needs over time. During this stage,  it’s necessary to:

• Periodically review the rearchitected application to ensure it continues to meet business goals. As technologies evolve and business needs change, be prepared to adapt the architecture accordingly.
• Leverage the new architecture to introduce innovative features, scale the application, or expand into new markets. The flexible architecture should enable quicker and more efficient development of future enhancements.

Rearchitecting is a challenging process that requires careful planning, execution, and an expert development team.  By following these steps, you can ensure that their applications are modern, scalable, and aligned with their business objectives.

10 Challenges of Legacy Software Rearchitecting

Rearchitecting legacy software may present some challenges, largely due to the complexities and constraints associated with older systems. Here are some of them:

1. Understanding the existing system. Legacy systems often suffer from poor or outdated documentation, making it difficult to fully understand the system’s architecture, functionality, and dependencies. Also, the codebase of legacy systems is often large, complex, and convoluted, which makes it challenging to identify how different parts of the system interact and where changes should be made.
2. Technical debt. Legacy systems usually have accumulated a significant amount of technical debt over the years, including outdated technologies, ad-hoc patches, and workarounds, which complicate the rearchitecting process. The existing architecture may be rigid and difficult to modify or extend, requiring substantial refactoring or rewriting of large portions of the code.
3. Dealing with outdated technologies. Legacy systems often rely on outdated or obsolete tools, frameworks, and libraries that are no longer supported, making it challenging to maintain and modernize. Ensuring that new technologies can integrate with or replace old technologies without breaking the system is a major challenge.
4. Business continuity. There is always a risk that rearchitecting could disrupt business operations, especially if the legacy system is mission-critical. Ensuring smooth transitions without downtimes is difficult. Teams often have to balance the need to keep the legacy system running smoothly while simultaneously working on the new architecture, which can strain resources.
5. Data migration. Migrating data from legacy systems to a new architecture can risk data loss, corruption, or integrity issues, especially if data formats or storage systems are vastly different. Understanding how to map and transform data between the old and new systems can be complex and error-prone.
6. Organizational resistance. Teams and stakeholders may be resistant to rearchitecting due to familiarity with the legacy system, fear of change, or concern over the cost and effort involved. The team may lack the necessary skills or experience with modern technologies, requiring training or the hiring of new talent.
7. Budget and time constraints. Rearchitecting a legacy system can be expensive, requiring investment in new technologies, training, and potentially additional staff. The process can be time-consuming, especially if the system is large and complex, making it difficult to deliver quick results.
8. Regulatory and compliance challenges. Legacy systems often need to comply with industry regulations, and ensuring that the new architecture meets these requirements can be challenging, particularly if regulations have evolved since the original system was built. Modernizing data handling to comply with current privacy laws (like GDPR) may require significant changes to how data is processed and stored.
9. Integration with other systems. Legacy systems often have many interdependencies with other systems, both internal and external, which complicates the process of rearchitecting. Updating or replacing APIs and interfaces is important to ensure they work with the new architecture while maintaining compatibility with other systems can be difficult.
10. Risk management. The complexity of legacy systems can lead to unforeseen issues during rearchitecting, such as hidden bugs, unexpected dependencies, or performance degradation. Developing and implementing effective rollback plans in case the rearchitecting fails or causes issues can be complex and resource-intensive.

Addressing these challenges requires careful planning, a deep understanding of the existing system, strong stakeholder engagement, and a phased, iterative approach to minimize risks and ensure a successful rearchitecture process.

The good news is that you don’t need to be an expert in tackling rearchitecting challenges to ensure your project’s success. At MobiDev, our tech consultants will choose the most suitable rearchitecting strategies tailored to address your specific business challenges. Our team will handle all the technical details, allowing you to focus on your core business objectives while we improve your application’s performance, maintainability, and scalability.

Best practices for successful application rearchitecting 

There are certain general best practices to overcome the challenges described above and successfully modernize. Here are some of them:

1. Pay attention to the initial audit of the current architecture. Evaluate the existing architecture to determine its readiness for the cloud. Identify dependencies, performance bottlenecks, and components that need significant changes to fit a cloud environment. Analyze which workloads are best suited for the cloud and which might be better kept on-premises or in a hybrid model.
2. Define clear goals. Align the cloud rearchitecting effort with business objectives, such as improving scalability, reducing costs, enhancing performance, or enabling global reach. Establish clear metrics for success, such as improved response times, reduced infrastructure costs, or faster deployment cycles.
3. Choose the right cloud model. Decide whether to use Infrastructure as a Service (IaaS), Platform as a Service (PaaS), or Software as a Service (SaaS), depending on your application’s needs. Choose between public, private, or hybrid cloud models based on security, compliance, and performance requirements.
4. Implement cloud-native principles. This allows you to take full advantage of cloud scalability, flexibility, and resilience. Use containers and orchestration tools like Kubernetes to manage applications in a consistent and scalable manner across cloud environments.
5. Prioritize security and compliance. Integrate security into every aspect of the cloud architecture, including identity and access management, encryption, and secure APIs. Ensure that the cloud architecture meets regulatory requirements such as GDPR, HIPAA, or other industry-specific standards, especially if data is stored or processed across multiple regions.
6. Plan for data management and migration. Develop a clear data strategy that includes data migration, storage, backup, and disaster recovery. Consider data sovereignty and compliance issues in different regions. Use cloud-native tools and services for seamless data migration, ensuring data integrity and minimizing downtime during the transition.
7. Leverage cloud services and automation. Take advantage of managed cloud services for databases, messaging, monitoring, and security, to reduce operational complexity and focus on core business functions. Automate infrastructure provisioning, deployment, and scaling using Infrastructure as Code (IaC) tools like Terraform or AWS CloudFormation.
8. Implement a CI/CD pipeline. Set up CI/CD pipelines tailored for cloud environments to automate testing, building, and deployment processes. This guarantees faster and more reliable releases. Ensure that development, testing, and production environments are as similar as possible to reduce the likelihood of issues during deployment.
9. Optimize for performance and cost. Continuously monitor and right-size cloud resources to avoid over-provisioning and control costs. Use auto-scaling to match resource allocation with actual demand. Implement monitoring and alerting systems to track the performance of cloud services and applications, enabling quick identification and resolution of issues.
10. Implement robust monitoring and management. Use cloud-native monitoring tools like AWS CloudWatch, Azure Monitor, or Google Cloud’s Operations Suite to gain visibility into application performance, resource utilization, and security. Implement centralized logging to collect and analyze logs across the cloud environment, facilitating troubleshooting and security audits.
11. Enable continuous improvement and innovation. Set up feedback loops to continuously gather insights from monitoring data and user feedback, allowing for ongoing optimization and innovation. Invest in training for your team to stay updated with the latest cloud technologies and best practices, ensuring they can fully leverage cloud capabilities.
12. Plan for disaster recovery and business continuity. Consider deploying applications across multiple regions or availability zones to enhance resilience and ensure business continuity in case of a regional outage. Implement automated backup and restore processes, ensuring critical data is regularly backed up and can be quickly restored in the event of a failure.
13. Conduct a post-migration review. After the migration, review the system’s performance and costs against the initial objectives and success criteria. Identify areas for further optimization. Document lessons learned during the rearchitecting process to inform future cloud migrations or optimizations.

By following these best practices, organizations can effectively rearchitect their software for the cloud, maximizing the benefits of cloud app modernization while minimizing risks and ensuring a smooth transition.

MobiDev Experience: App rearchitecting success stories

At MobiDev, we’ve helped numerous clients overcome rearchitecting hurdles through strategic rearchitecting, enabling them to streamline operations, improve performance, and accelerate growth. The following success stories from our experience highlight how properly implemented rearchitecting can transform applications and deliver significant business benefits.

Success story #1. MODERNIZING SAAS PLATFORM FOR EDUCATION & MENTORING

A US-based education company developed a platform to connect applicants with mentoring students. However, as time passed, the platform became outdated, unstable, and unable to meet the evolving needs of its users. The company sought MobiDev’s expertise to modernize the application, redevelop its architecture from scratch, and expand its reach to a new target region, while also ensuring ongoing support.

How we delivered:

1. Software audit and tech strategy development. Before diving into development, we performed a comprehensive software audit to pinpoint the platform’s limitations. We then created a detailed tech strategy to guide the architecture redevelopment, ensuring the selection of an optimal tech stack for a more robust and future-proof solution.
2. Rebuilding the architecture from scratch. The MobiDev team took on the challenge of rewriting the platform’s architecture from the ground up. This complete overhaul was essential for optimizing performance and addressing the stability issues that had plagued the existing system.
3. Launching two independent platforms for different markets. Originally designed for the US market, the platform needed to expand its reach to Asian high school students seeking US-based mentors. We cloned the platform, implemented a separate API and database, and created a completely independent platform to cater to this new market.
4. Optimizing performance. To ensure the platform’s reliability and stability for a large user base, we focused on reducing server load and optimizing performance. This involved transitioning from an Ansible-based deployment to a continuous integration system, enhanced with Fabric, Jenkins, and API autotests to streamline operations.

Key business outcomes:

1.  Through our rearchitecting efforts, the client’s platform was transformed into a modern, stable, and scalable solution.
2. The unified and optimized architecture not only enhanced performance but also enabled the company to successfully launch a new platform tailored to a different market. 
3. With reduced server loads, improved reliability, and an adaptable cooperation model, the client is now well-positioned to meet the needs of their expanding user base and continue their growth trajectory.

Success story #2. Moving from Monolith to Microservices

Our client, a rapidly growing startup, faced significant challenges due to the use of multiple technology stacks: WordPress and Ruby on Rails (RoR) across their services. This made it difficult to maintain a consistent engineering team, imitating their ability to develop new features quickly. The startup’s initial architecture design was also becoming a bottleneck, slowing down the overall development process.

How we delivered:

1. Audit and choosing a rearchitecting approach. We reviewed the current state of the application and concluded that the existing architecture does not meet the client’s requirements and does not allow for scalability. To address these challenges, our team undertook a comprehensive rearchitecting of the client’s platform.
2. Transitioning the platform from a monolith approach to microservices. The team unified the tech stack by rewriting the WordPress components of the project using Ruby on Rails. This not only streamlined the development process but also allowed for more cohesive team management. 
3. Implementing a microservices architecture. We introduced a microservices architecture that effectively isolated multiple applications from each other while enabling seamless data sharing between them, such as user information. 
4. To further reduce risks associated with new releases, we implemented Continuous Integration/Continuous Deployment (CI/CD) automation.

Key business outcomes:

1. The rearchitecting efforts led to significant improvements in the client’s operations.
2. The unified tech stack allowed for more efficient use of engineering resources and faster development of new features. 
3. The microservices architecture enhanced the system’s stability and performance, and the CI/CD automation reduced the risks during releases, resulting in a smoother and more reliable deployment process.

Overall, the client saw increased development velocity, improved system reliability, and a more scalable architecture, positioning them for continued growth.

Start your rearchitecting journey with MobiDev

At MobiDev, we bring over a decade of experience in building, scaling, and modernizing software products. Our team of in-house consultants and engineers will audit your existing software and infrastructure to create a clear, tailored roadmap that aligns with your business goals. We specialize in cloud migration services, including Google Cloud, Azure, and AWS, ensuring a seamless migration process that is both efficient and secure.

With our in-house DevOps team, you don’t need to look for other resources to streamline the cloud migration process, minimizing the risk of errors and guaranteeing a smooth transition to the cloud. We understand the complexities of compliance, and our expertise spans critical standards such as GDPR, CCPA, HIPAA, GLBA, and PCI DSS. Our approach not only meets these regulations but also strengthens your product’s security and reliability. Choose MobiDev for your application rearchitecting, and let us help you build a future-ready, scalable solution that drives your business forward.