Petrobras had more than 2,000 legacy applications and an IT organization so consumed by maintenance that there was no capacity left for innovation. Bosch was managing a two-year development backlog that was stalling digital transformation across its factories. Axos Bank was buried in COBOL code that needed modernizing, but the traditional path to doing so was prohibitively long and expensive.
These are not unusual situations. Most enterprise organizations are managing some version of this problem, a core systems landscape that was built for a different era, consuming more and more IT resources just to keep running, while the business demands faster innovation and AI capabilities the existing infrastructure was never designed to support.
The instinct is to start over. Rip it out, replace it, rebuild from scratch. That instinct is almost always wrong.
The Legacy Modernization Trap Most Enterprises Fall Into
Full replacement projects are the most expensive, most risky, and most frequently delayed category of enterprise technology initiative. The scope is always larger than the initial estimate. The dependencies are always more complex than anyone anticipated. The timeline always extends. And the business, in the meantime, cannot stop running on the systems being replaced.
The organizations that have navigated legacy modernization most successfully have done so not by replacing what they have, but by extending it intelligently, building a modern, intelligent layer on top of existing infrastructure that preserves the business logic, data, and stability embedded in those legacy systems while dramatically expanding what they can do.
That is the approach OutSystems enables. And combined with AI capabilities like OutSystems Mentor and Agent Workbench, it is producing results that would have seemed implausible with traditional modernization approaches.
Why Traditional Approaches to Legacy Modernization Fail
The legacy modernization problem has been around long enough that organizations have tried most of the available approaches. Three failure modes show up most consistently.
Full replacement underestimates complexity. Replacing a core system that has accumulated decades of business logic, integrations, and institutional knowledge is never as clean as the initial scoping suggests. Dependencies that were not documented surface during migration. Data quality issues that existed beneath the surface of the old system become visible and painful in the new one. Timelines expand. Costs escalate. And the business bears the risk of operating on a partially migrated landscape for longer than anyone planned.
Point-in-time integrations create new technical debt. Connecting modern applications to legacy systems through custom integration layers solves the immediate problem but creates a maintenance burden that compounds over time. Every change to either system requires updating the integration layer. Every new capability requires another custom connection. The technical debt accumulates faster than the value generated.
AI coding tools generate code without governance. The newer wave of AI-assisted development tools can accelerate code generation significantly, but they do not provide the governance, dependency management, security validation, or lifecycle management that enterprise-grade applications require. The result is faster-generated code that still requires extensive manual review, security hardening, and integration work before it can be trusted in production, and which often introduces new inconsistencies into an already complex codebase.
How OutSystems Approaches Legacy Modernization Differently
OutSystems takes a fundamentally different approach to the modernization problem, built around two core principles.
The first is wrap and extend rather than replace. OutSystems connects to existing legacy systems through 400+ pre-built connectors, native MCP support, and plug-and-play tools that can call virtually any API or service. Rather than requiring a wholesale replacement of what exists, OutSystems builds a modern application and agent layer on top of existing infrastructure, preserving the business logic and data that are embedded in legacy systems while giving users and processes a dramatically improved experience.
The second is the OutSystems Model, or OML, which is the underlying technical architecture that makes this approach reliable at enterprise scale. OML maps your entire enterprise context, including your custom-built systems, external systems, data sources, and third-party agents, before any new code is compiled. It automatically tracks dependencies across all components, ensuring that compiled code is secure, reliable, and scalable by design. When Mentor, OutSystems’ AI-powered development assistant, modernizes a legacy application, it does so with the full portfolio context already in place, which is why Axos Bank was able to skip what is normally a ten-step process for moving off COBOL or .NET, modernizing core applications almost instantly.
Bosch: From a Two-Year Backlog to 500 Applications in Four Years
Bosch, one of the world’s most recognizable manufacturing brands, was facing a development backlog that was stalling industrial innovation. The backlog was not a capacity problem alone. It was compounded by shadow IT, teams building their own workarounds outside the oversight of IT because the official development process was too slow to keep pace with business needs.
By adopting OutSystems, Bosch built more than 500 productive applications in four years, including their standout AIoT factory planning and support app. This AI-powered solution enables human-robot collaboration at scale, using AI to identify the skills required for each machine on an assembly line, match them with the right worker, and account for physical condition and resource availability in real time. The result was an 85% reduction in assembly line ramp-up time for new production lines.
The broader outcome was a cultural and operational shift. As Bosch’s Group Manager of Low-Code Experts described it, OutSystems allows the team to build something instead of pushing it into a two-year backlog. That ability to say yes rather than no, consistently and quickly, is what enables sustainable transformation rather than one-off modernization projects.
Petrobras: 2,000+ Legacy Apps, 15x ROI, and an Agentic Future
Petrobras is a global energy company with more than 41,000 employees and annual revenues of $91 billion. When the organization adopted OutSystems, it did so to address a problem that will sound familiar to most enterprise IT leaders: a sprawling legacy application estate consuming so much maintenance effort that innovation was effectively impossible.
By deploying OutSystems across more than 100 agile teams organized into a center of excellence, Petrobras shifted from a maintenance-heavy posture to delivering 48 mission-critical applications in just eight months, with more than 400 deployments happening every month and some projects achieving a 15x return on investment.
That transformation then became the foundation for something more ambitious. The Petrobras Digital Audit team built Raí, an AI agent using OutSystems Agent Workbench that leverages natural language to let auditors instantly query regulatory standards, risks, and past audits without navigating complex systems or waiting on manual research. A process that previously took days of careful manual work now takes five minutes. The team is already expanding the agentic solution to include agents that auto-generate reports, compounding the efficiency gains further.
Axos Bank: Modernizing Core Banking Without Replacing It
Axos Bank was dealing with a challenge that many financial institutions know well: a core banking environment with legacy code that needed modernizing, but where the traditional modernization path was a lengthy, expensive, and risk-laden process.
Using OutSystems Mentor, Axos was able to modernize legacy COBOL and .NET applications almost instantly, with full enterprise portfolio context already mapped by OML, effectively skipping the ten-step process that legacy code modernization typically requires. The results across the modernization initiative were significant: 60% faster development, a 75% reduction in defects, and an 85% decrease in rework.
With the modernized foundation in place, Axos then used Agent Workbench to build an intelligent agent that handles error log analysis and complex document mapping automatically, eliminating hours of manual operational work and building the kind of agentic capability the team is now expanding across additional use cases.
What a Smart Legacy Modernization Roadmap Looks Like
The organizations that get legacy modernization right share a few characteristics in their approach that distinguish them from those that struggle.
They start with an honest inventory. Before any modernization work begins, understanding what exists, how it is used, how much of it is actively maintained, and what its dependencies are provides the foundation for every subsequent decision. Organizations that skip this step consistently underestimate scope and overestimate how much they can modernize quickly.
They sequence by impact rather than by complexity. The temptation is to start with the most complex legacy systems because they feel like the biggest risk. In practice, starting with high-visibility, high-impact use cases builds the internal momentum, organizational confidence, and platform familiarity that make subsequent, more complex modernization efforts more likely to succeed.
They establish governance before they build. The power of a platform like OutSystems is that it makes development faster for everyone, including teams that would otherwise build outside IT’s oversight. Establishing clear governance standards, development practices, and portfolio management processes before the platform scales across teams is what prevents the shadow IT problem from simply re-emerging in a new form.
They treat modernization as an ongoing program rather than a one-time project. The organizations achieving the most impressive results with OutSystems, including Petrobras with its center of excellence and Bosch with 400 active developers, have treated adoption as a continuous capability rather than a migration project with an end date.
How Optimum Helps Organizations Modernize Legacy Systems with OutSystems
Optimum’s approach to OutSystems legacy modernization starts with assessment. Before recommending any implementation path, we work with your team to understand your current application landscape, identify modernization priorities, map integration dependencies, and develop a phased roadmap that sequences work to deliver early value while building toward a broader transformation.
Our cross-platform expertise matters here in ways that a pure OutSystems partner cannot replicate. Legacy modernization rarely happens in isolation. It involves ERP systems, Microsoft platforms, data and analytics infrastructure, security and compliance frameworks, and workflow automation that spans multiple tools. Optimum’s experience across Microsoft 365, Make.ai, ServiceNow, and data and analytics through platforms like Microsoft Fabric means we design OutSystems modernization initiatives that fit into your full technology landscape rather than creating a new silo alongside everything else.
Ready to move beyond maintenance mode and start modernizing with AI? Talk with us about OutSystems consulting services.
About Optimum
Optimum is a nationally recognized IT consulting firm and official partner of OutSystems, Microsoft, Make.ai, ServiceNow, and other leading enterprise platforms, dedicated to helping organizations build, deploy, and govern AI-powered applications that deliver measurable business outcomes.
We focus on driving efficiency, reducing operational costs, and supporting digital transformation through an assessment-led, partnership-driven approach. Our expertise spans legacy modernization, AI agent design, workflow automation, data and analytics, and enterprise platform implementation. We help organizations automate work and ensure that work is grounded in clean data and surfaces in the reporting environments leadership actually uses to make decisions.
Reach out today for a complimentary discovery session to explore how Optimum can help your organization modernize legacy systems with OutSystems.
Contact us: info@optimumcs.com | 713.505.0300 | www.optimumcs.com
