Platform engineering is transforming how enterprises modernize legacy systems, enabling organizations to dismantle monolithic applications gradually rather than through costly and disruptive “big-bang” rewrites.
By embedding secure APIs, automated delivery pipelines, observability and service discovery into developer workflows, platform teams can manage risk, maintain uptime and accelerate the transition to modern architectures.
Rather than replacing entire systems in one move, platform teams increasingly use the Strangler Fig Pattern—incrementally building new functionality around legacy systems and replacing them piece by piece.
“Platform engineering supports the gradual modernization of legacy systems by creating the infrastructure and tooling that make incremental change safe, fast and repeatable,” said Derek Ashmore, AI enablement principal at Asperitas.
With these tools, platform engineering transforms modernization into a manageable, continuous process — allowing teams to strangle the monolith over time while maintaining uptime and reducing disruption.
At the core of this approach are secure, well-governed APIs that expose legacy functions behind stable, decoupled interfaces.
These APIs help define clear service boundaries, enforce explicit contracts and reduce hidden dependencies during the breakup process. They also bring built-in security and compliance, as gateways enforce authentication, rate limits and auditability.
“Once functionality is exposed via APIs, other teams can reuse services without duplicating effort, accelerating innovation and reducing redundancy across the organization,” Ashmore said.
Alongside APIs, CI/CD pipelines and service discovery play a crucial role in keeping modernization efforts smooth.
Automated testing and continuous delivery pipelines help teams validate changes early and often, building confidence that updates won’t break existing functionality.
Service discovery then ensures that as components migrate from monoliths to microservices or from on-premises systems to the cloud, traffic is automatically routed to the correct version without requiring upstream changes.
“Together, CI/CD and service discovery create a resilient foundation for modernization,” Ashmore said. “They allow teams to apply patterns like the Strangler Fig, where old and new systems operate in parallel, with smooth transitions and minimal disruption to the business.”
As systems become more distributed, observability becomes the safety net ensuring reliability throughout the migration process.
This includes monitoring API performance, tracing requests across old and new components, and alerting on anomalies before they impact users.
“Metrics and logs provide feedback loops that help teams tune their CI/CD pipelines, rollback strategies and migration pacing,” Ashmore said. “Observability ensures migrations are not only possible — but reliable, traceable and reversible.”
Internal developer platforms (IDPs) further support modernization by embedding governance and standards directly into the development workflow.
They provide scaffolding, templates and automated API checks to ensure consistency without adding friction.
“IDPs are designed primarily to boost developer productivity and reduce cognitive overload,” Ashmore explained. “They offer golden paths for API development so developers follow pre-defined workflows that promote consistency, reduce boilerplate and minimize misconfiguration.”
While IDPs are crucial today, Ashmore noted that the rise of AI-assisted coding could reshape their role.
AI agents may increasingly generate validated, standards-compliant code, reducing the need for centralized platforms to enforce consistency, especially for new services built from scratch.
Still, in today’s complex enterprise environments, they remain an essential part of the platform engineering toolkit.
Ultimately, the API-first shift — powered by platform engineering — allows enterprises to modernize without jeopardizing uptime or overwhelming teams.
By taking an incremental, well-governed approach, organizations can gradually replace aging systems, safeguard business continuity and lay a foundation for long-term agility.
“Good platform engineering makes modernization less of a high-stakes gamble and more of a predictable, continuous improvement process,” Ashmore said. “That’s how you keep moving forward without breaking what’s already working.”