The 6 Rs of Application Modernization: Which One Fits Your Business?

Legacy systems may keep your business running, but they also hold you back. They’re expensive to maintain, slow to adapt, and often risky when it comes to security and compliance.

That’s why so many organizations are investing in application modernization: transforming legacy apps into cloud-native, agile solutions. But not every system requires the same approach. Enter the 6 Rs framework: a proven model from AWS that helps businesses decide the right modernization path.

In this guide, we’ll break down the 6 Rs, when to use each, and how to choose the right fit for your business.

What Are the 6 'R's of Modernization?

The 6 Rs are six strategies AWS recommends for migrating and modernizing applications:

1. Rehost (Lift-and-Shift)

Move applications to the cloud with minimal or no changes.

→ Best for: Quick migrations with limited budget or tight timelines.

→ Watch out: May not unlock full cloud benefits like scalability or cost optimization.

2. Replatform (Lift-Tinker-Shift)

Make small adjustments (e.g., using managed databases) while migrating.

→ Best for: Balancing speed and efficiency, gaining some cloud-native benefits quickly.

3. Refactor / Re-Architect

Rewrite applications to be cloud-native (e.g., microservices, containers, serverless).

→ Best for: Legacy systems that limit innovation or scaling.

→ Watch out: Requires more time and investment upfront.

4. Repurchase (Replace)

Retire an in-house app and switch to a SaaS alternative.

→ Best for: Commodity apps (like CRM or HR) where SaaS products already exist.

5. Retire

Decommission apps that are no longer needed.

→ Best for: Clearing out unused systems that still consume resources.

6. Retain

Keep certain apps in place (on-prem or legacy cloud) until there’s a better reason to modernize.

→ Best for: Apps with low business value or ones needed temporarily.

How to Decide Which 'R' Fits Your Business

Choosing the right approach depends on your business goals, compliance needs, and resources. Key factors include:

• Cost: Do you need a quick win or can you invest for long-term gains?

• Timeline: Is speed of migration more critical than optimization?

• Compliance: Do regulatory frameworks (HIPAA, PCI DSS, SOC 2) dictate specific architectures?

• Scalability: Does the app need to support rapid growth or global users?

• Innovation Needs: Do you want to leverage modern capabilities like AI/ML or serverless?

Common Mistakes in Modernization (and How to Avoid Them)

• One-size-fits-all migration: Not every app needs to be re-architected.

• Underestimating compliance: Skipping security design early leads to costly rework.

• Ignoring cost optimization: “Lift-and-shift” without optimization can drive AWS bills higher.

• Lack of collaboration: Modernization isn’t just IT, it requires input from business leaders, too.

Real-World Example

A healthcare startup approached Forged Concepts with a legacy app handling sensitive patient data. After analysis, we recommended a Replatform + Refactor strategy:

Migrated workloads to AWS using managed services.

Re-architected critical components with serverless (Lambda) and containers (ECS).

Ensured HIPAA and SOC 2 compliance from day one.

Result: Faster deployments, improved scalability, reduced costs, and full compliance, enabling the startup to serve clients more confidently.

Conclusion: Build the Right Roadmap

The 6 Rs framework gives businesses a structured way to modernize, but the right path depends on your unique needs. Whether it’s a quick lift-and-shift or a full refactor, choosing wisely means balancing cost, speed, compliance, and innovation.

Unsure which “R” fits your business? Forged Concepts helps companies build tailored modernization roadmaps using AWS best practices so you can move forward with confidence.

Talk to our experts and start building your cloud-native future today.

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