Migrating to MuleSoft: an ex-Muley’s perspective

As organisations embrace digital transformation and AI, modernising legacy integration platforms becomes a critical step in unlocking the full potential of emerging technologies. Legacy integration platforms often struggle to support the speed, scalability, and flexibility required by modern applications, hindering data flow and real-time decision-making capabilities. In the age of AI, where data is the driving force behind intelligent automation, predictive analytics, and personalised experiences, outdated integration infrastructures are no longer sufficient. By modernising to API-led integration platforms, organisations can break down data silos, streamline workflows, and ensure seamless connectivity across cloud-based applications, on-premises systems, and third-party services. This not only facilitates more efficient and innovative operations but also lays the foundation for leveraging AI to drive smarter business outcomes, improve customer experiences, and gain a competitive edge.

Migrating from a legacy integration platform to a modern solution like MuleSoft is a complex undertaking that impacts architecture, operations, business processes, and people. Treating it as a discrete IT project often leads to siloed execution, missed dependencies, and limited long-term value. Instead, a program approach ensures that the migration is planned and executed as a coordinated, enterprise-wide transformation initiative. This allows for better governance, prioritisation, change management, and alignment with broader digital strategies.

A programmatic approach also provides the structure needed to address foundational enablers, such as platform governance, reusable API libraries, CI/CD pipelines, and skills development, before scaling into full migration. By organising the migration into strategic phases (discovery, enablement, pilots, scaling, and optimisation), enterprises can mitigate risk, manage resource demand, and deliver measurable value early and often. It allows leadership to track progress against business outcomes, not just technical milestones, ensuring that integration becomes an enabler of agility, innovation, and customer-centricity.

This blog outlines a strategic, phased approach to migrating from legacy integration platforms to MuleSoft. It provides a clear roadmap for enterprises seeking to modernise their integration capabilities, reduce technical debt, and enable enterprise-wide agility.

Phase 1: Foundation and Discovery

The first phase is crucial for understanding the key activities, people and costs that will ensure a successful migration. The focus is on understanding the current state, identifying business goals, and establishing a roadmap for the entire migration effort.

The process begins with taking a stocktake of the existing integrations and key dependencies. This assessment helps establish a clear understanding of what the organisation currently relies on and the pain points tied to the legacy platform. For each legacy integration a decision should be made if they are to be migrated, retired as they are no longer required, or fundamentally re-designed and re-architected to meet changing business requirements. By the end of this phase, a migration roadmap and a target architecture based on an API-led approach is crafted, outlining how the new integrations will be structured using System, Process, and Experience APIs.

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Phase 2: API Prioritisation

Rather than diving into the migration, organisations should prioritise the APIs that will be most beneficial to migrate first. This phase focuses on identifying and ranking the key APIs that will drive business value early in the migration process.

API prioritisation begins with defining key criteria for selecting APIs to migrate. Business criticality, integration complexity, potential for reuse, and the ability to modernise legacy processes are the primary factors that should be weighed. By applying a structured scoring system to each API, businesses can identify which APIs will provide the most immediate benefits, both in terms of business value and ease of migration.

For example, APIs that support core customer-facing processes or regulatory requirements should be prioritised to ensure that the migration addresses the most urgent business needs. At the same time, tackling some quick-wins, can demonstrate the capabilities of the new platform early on and build trust, confidence and momentum within your organisation that the program will deliver meaningful results.

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Phase 3: Platform Enablement

With the APIs prioritised and the foundational business case in place, the next step is to set up the MuleSoft platform and ensure it is configured to meet enterprise requirements. This phase involves the setup of the Anypoint Platform, including defining development standards, governance frameworks, API design standards, security policies, and approaches to version control. Reusable assets such as connectors, logging frameworks, and error handling flows should be also created to speed up future development. Additionally, CI/CD pipelines should be set up to automated your SDLC and any training required for your development squads.

One often overlooked aspect of platform setup is adequate capacity planning, both from a technical and commercial perspective. This has increased in importance since MuleSoft has introduced their new capacity based pricing models. Without this, migration efforts often falter due to cost blow-outs or inadequate capacity to meet the programs demands.

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Phase 4: Pilot Migration

The next phase involves a pilot migration to test the approach with a subset of integrations. This phase helps validate the chosen methodologies, uncover any potential challenges, and build confidence in the new platform.

The pilot involves migrating a small set of integrations, chosen based on the prioritisation matrix created in the previous phase. These integrations are carefully selected to be business-critical but of moderate complexity. The team will rebuild these integrations using MuleSoft’s API-led design principles and run them in parallel with legacy systems to ensure functionality and performance are met.

Throughout the pilot, lessons learned are captured, and the migration methodology is refined for broader deployment. The results of this phase help adjust the program approach, ensuring that the full migration will be smoother and more efficient.

Phase 5: Full-Scale Migration

Following a successful pilot, the organisation moves into the full-scale migration phase, where all legacy integrations are either migrated, re-designed or decommissioned according to the roadmap. This phase is executed in waves, allowing the migration to be managed in stages and ensuring minimal disruption to business operations.

Each wave focuses on migrating a group of integrations, beginning with the most critical or high-value APIs, and gradually expanding to include all legacy systems. As integrations are moved, legacy systems are decommissioned, and the organisation moves toward a fully modernised, API-led architecture. Security and compliance remain a top priority during this phase, ensuring that all data and transactions meet regulatory requirements.

The change management strategy also plays a crucial role in this phase, supporting users and stakeholders with communication, training, and feedback loops to ensure smooth adoption and minimise resistance.

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Phase 6: Optimisation and Continuous Improvement

Once the full migration is complete, the focus shifts to optimisation and continuous improvement. The platform should be monitored for performance, and KPIs are tracked to ensure the integration architecture is operating at peak efficiency. While this sounds obvious, many clients in my experience neglect to setup the proper alerting and monitoring, which is often not realised until either an incident causes an outage or capacity limits are breached. If the client is on transaction based pricing, this can cause ‘sticker shock’ when the bill for exceeding flows or transactions is realised.

APIs should be regularly reviewed for performance, and teams encouraged to promote the reuse of existing APIs to reduce duplication and foster efficiency. As new business requirements emerge, the organisation should aim to use the new API assets for new areas, such as integrating with AI-driven platforms, or enabling new services and business models.

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Why you need to choose the right partner

Having the right partner is critical to the successful execution of a MuleSoft migration program. While MuleSoft provides a powerful platform for modern integration, the complexity of transitioning from a legacy environment means that technical capability alone is not enough. A seasoned integration partner brings the experience, frameworks, and cross-functional expertise required to navigate the technical, organisational, and strategic dimensions of such a transformation.

A qualified partner offers deep knowledge of both legacy platforms and MuleSoft, enabling them to design migration strategies that minimise disruption and maximise reuse. They help identify integration patterns, assess technical debt, and develop robust API-led architectures aligned with business goals. More importantly, a partner can provide proven accelerators, reusable assets, and delivery methodologies that reduce time to value and ensure consistent outcomes across workstreams.

Additionally, a good partner supports your organisational change management activities, a key success factor that is often overlooked. They help upskill internal teams, educate executives, align stakeholders, and foster a culture of API reuse and agile delivery. With the right partner, businesses can avoid common pitfalls, mitigate risks, and drive the transformation with confidence, ensuring that the migration to MuleSoft is not just a technical project, but a catalyst for enterprise-wide agility and innovation.

Conclusion

Modernising from legacy integration platforms to MuleSoft is more than a technology transition, it’s an enterprise transformation enabler. By embracing a structured, phased approach and aligning with business priorities, organisations can unlock agility, drive operational efficiency, and create a resilient digital backbone.