Reclaim control from legacy bloat

Modernize your core without losing the business logic that got you here

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  • 80+
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  • 5+
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  • 100%
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Our process

How we modernize legacy systems using OutSystems

Legacy landscape discovery

We conduct a technical and functional audit of your existing system, understanding key dependencies, workflows, and pain points.

Business logic extraction

We identify and isolate core rules, processes, and data flows that are worth preserving.

Architecture redesign

We redesign the architecture using OutSystems reusable modules, built for scale, integration, and performance.

Migration & testing

We safely migrate data, integrate with external systems, and conduct UAT to ensure zero functional gaps.

Deployment & monitoring

With OutSystems Lifetime, we deploy and monitor the new system with rollback options and continuous optimization in place.

Tech talk

Developer tips & insights

OutSystems legacy system re-engineering FAQs – Modernize without the Mayhem in 2026

Your go-to guide on preserving core logic, zero-downtime transitions, AI-assisted refactoring, and phased modernization that actually works

Legacy systems slow you down, we turn that around by keeping your proven business logic intact while shifting to a fast, scalable, low-code foundation. We start with deep audits to map dependencies and extract rules, then apply the strangler pattern and bimodal architecture to layer OutSystems on top, exposing legacy via secure API gateways with caching, throttling, and circuit breakers. Data migrates safely through async syncs and validation, UI/UX gets reactive and modern, integrations hit 10x speed with pre-built connectors, and OutSystems Lifetime handles deployment, rollback, and ongoing monitoring for 99.9% uptime. This is the practical way to reduce maintenance costs 70%, boost agility, eliminate big-bang risks, and make your enterprise apps future-ready without disruption.

Assess based on business urgency, system complexity, and ROI: rehost (lift-and-shift) for quick wins on stable, non-critical apps needing cloud scalability without changes. Refactor if the core logic is solid but UI/performance lags—wrap legacy in APIs and build OutSystems facades for gradual enhancement. Rebuild from scratch only for high-complexity, rigid systems where full redesign unlocks 5-10x agility; pilot a small domain first to validate. Prioritize by running Architecture Dashboard scores and user pain points.
Assess/inventory apps with AI Mentor/Discovery for dependencies and debt. 2. Define domains and pilot MVP screens in dual-run (old/new side-by-side). 3. Build API wrappers for legacy data, migrate high-traffic screens first via automation. 4. User-test iteratively with approvals before cutover. 5. Monitor via LifeTime, decommission old modules progressively. This phased approach ensures zero-downtime, typically 6-12 months for enterprise scale by focusing risk on small batches.
Layer OutSystems as a "strangler pattern" facade, expose legacy functions via stable APIs while rebuilding user-facing layers progressively, keeping core backend intact. Use reactive modules for new features, AI Mentor to flag/refactor spaghetti code, and domain-driven modules to isolate debt. This hybrid cuts maintenance 70% by offloading UI/logic to visual low-code, eases team upskilling, and allows phased retirement without big-bang risks.
Design a "bimodal" architecture: dedicated Integration Services module consumes legacy APIs/DB views, aggregates data, and exposes clean entities/actions to UI/Logic apps. Keep legacy as system-of-record (read-only where possible), use queues/timers for async syncs, and modularize by business domain. This decouples front-end agility from back-end stability, enabling parallel evolution and easy swaps later.
Create a thin API gateway module in OutSystems that calls legacy via secure connectors (JDBC for DB, SOAP/REST wrappers for mainframes), adding caching and throttling. Implement circuit breakers for resilience, encrypt sensitive calls with SSL, and version endpoints. Test with synthetic data first, monitor latencies in production—this shields modern apps from legacy volatility while enabling incremental replacement.
AI Mentor auto-detects migration candidates, generates reactive screens from legacy ones, and flags anti-patterns for 50% faster refactoring. Drag-drop visual dev replaces manual coding, pre-built connectors speed integrations 10x, and one-click deployment/publishing eliminates devops overhead. Teams deliver MVPs in weeks vs. years, iterating via citizen dev for UI while pros handle logic, proven to slash timelines via reuse and automation.
Key risks: data inconsistencies (mitigate with replication/validation timers), performance regressions (profile aggregates, use external DB indexes), and scope creep (fix via domain prioritization). User resistance, pilot with feedback loops; skill gaps—train via Forge accelerators. Start small, dual-run environments, and leverage ODC-readiness audits for long-term viability, ensuring 99.9% uptime.

Reclaim control from legacy bloat.

Modernize with OutSystems: audit landscapes, extract business rules, and deploy with rollback options for seamless transformation.