Switching to a new core banking platform is supposed to fix integration problems, not create new ones. But for one $2 billion federal credit union serving tens of thousands of members across multiple states, the move to Corelation KeyStone solved most of its technology challenges while leaving one stubborn gap wide open: the mortgage team's loan origination system couldn't talk to the new core.
After every closed loan in Calyx Path, staff had to re-enter the same borrower data, loan terms, and servicing details into KeyStone by hand. The core conversion had modernized nearly everything else, but the LOS-to-core handoff was still a manual, error-prone process that ate hours every week.
It's a pattern that plays out at credit unions across the country. The core gets upgraded. The digital banking platform connects. The LOS stays on an island.
This credit union had done the hard part. It completed a full core conversion to Corelation's KeyStone platform, consolidating data and gaining access to KeyStone's modern open API architecture. It selected a new digital banking platform specifically for its tight integration with KeyStone, giving members a seamless experience across channels.
But mortgage lending sat outside that integration perimeter. Calyx Path, the LOS, had no native connection to KeyStone. Every closed loan required manual data transfer, and every manual step introduced the same problems the core conversion was supposed to eliminate:
The credit union had invested months of planning, budget, and staff time into the KeyStone conversion. The ROI on that investment was being quietly eroded every time someone sat down to retype a closed loan.
Credit unions often assume that moving to a modern core with open APIs will make third-party integration straightforward. In practice, it's rarely that simple. The LOS vendor and the core vendor build their APIs independently, with different data models, field naming conventions, and validation rules. Someone has to build and maintain the translation layer between them.
Corelation KeyStone's open API architecture makes integration possible, but it doesn't make it automatic. The credit union still needs middleware that understands both systems, maps fields accurately, validates data before it moves, and handles exceptions when records don't match expected formats.
This is where most credit unions get stuck. The IT team that just spent months or years on a core conversion doesn't have bandwidth to build a custom LOS integration from scratch. And the LOS vendor isn't going to build it for them. The result is a familiar compromise: staff become the middleware, manually bridging the gap between systems that were each supposed to make things easier.
The problem is growing. Corelation signed 27 new credit unions for KeyStone conversions in the first three quarters of 2025, with go-live dates stretching through 2027. Wings Credit Union, a nearly $20 billion institution formed from a merger, cited integration capabilities as a primary reason for choosing KeyStone. Every one of those credit unions will face the same LOS integration question this institution faced.
What makes this problem persistent is how effectively it hides. Executives see closed loan numbers on a dashboard. Board members review growth in quarterly reports. Members experience their mortgage closing as a milestone. Nobody sees the hours of clerical work happening behind the scenes to move that data from one system to another.
But the costs accumulate. Research from McKinsey found that financial institutions running legacy or disconnected systems face operating costs up to 10 times higher than those with integrated platforms. Most of that gap comes from exactly this kind of manual process: staff time, error correction, compliance remediation, and the opportunity cost of skilled employees doing work that software should handle.
For credit unions specifically, the staffing math is brutal. Loan officers who spend two hours per day on data re-entry aren't available for member consultations, pipeline management, or processing new applications. Over the course of a year, that's roughly 500 hours per loan officer redirected from revenue-generating activity to clerical work. Multiply that across a mortgage team of four or five people, and the hidden cost becomes a significant line item that never appears in any budget.
And the compliance dimension adds another layer. Regulators don't care why the LOS and core show different numbers. They care that they do. A pattern of discrepancies between systems can escalate from a minor finding to a matter requiring attention, which means management response plans, board reporting, and examiner follow-up during the next exam cycle.
The credit union partnered with Access Business Technologies to deploy a cloud-managed integration layer connecting Calyx Path and Corelation KeyStone. Instead of building custom code or asking staff to keep bridging the gap manually, ABT stood up a managed middleware service that handled the entire data pipeline.
Here's what the integration delivered:
Manual re-entry stopped immediately. Staff no longer typed the same data twice. The hours they recovered went back to loan processing, member service, and new application intake. The mortgage team's daily workflow changed from the first day the integration went live.
Data quality improved across the board. Automated validation caught formatting errors, missing fields, and inconsistencies that manual re-entry had been introducing for years. Loan records matched across both systems from the moment of closing. Quality assurance shifted from catching transcription errors to reviewing the exception cases flagged by the rules engine.
Members noticed faster service. New mortgages appeared in online banking and member account screens within minutes of closing, not days. The "when will my mortgage show up?" calls to member service dropped significantly. Members experienced the kind of real-time responsiveness they expected from a credit union that had just modernized its core platform.
Compliance risk shrank. With identical data in both the LOS and core, the credit union could hand NCUA examiners a consistent set of records without spending days reconciling discrepancies. The automated audit trail replaced the patchwork of manual logs that had covered the gap before. Every data movement was logged, timestamped, and traceable.
The core conversion investment paid off fully. KeyStone's modern architecture was finally connected to every system that mattered, including the mortgage operation that generates some of the credit union's most complex and regulated data. The ROI story for the core conversion became complete.
The lesson here extends beyond credit unions running Corelation and Calyx. Any financial institution upgrading its core banking platform needs to include LOS integration in the project plan from the start. A modern core with open APIs is a foundation, not a finish line. Without middleware connecting the LOS, the mortgage operation remains an island of manual processes surrounded by automation.
The credit unions converting to KeyStone in 2026 and 2027 have an opportunity to avoid this trap entirely by planning the LOS integration alongside the core conversion rather than treating it as a "phase two" project that never quite happens. The same applies to institutions on Fiserv, Symitar, or any other core platform with LOS integration gaps.
For institutions running technology stacks from multiple vendors, a cloud-first managed service provider can build, host, and maintain those integrations as an ongoing service. That's a fundamentally different model from building custom integrations in-house, where every vendor update can break the connection and every API change requires developer time the credit union may not have.
ABT serves 750+ financial institutions as a cloud-first MSP and Tier-1 Microsoft CSP, with deep experience connecting LOS platforms, core banking systems, and the compliance infrastructure that holds them together.
A modern core banking platform is only as valuable as the connections it maintains with the rest of your technology stack. This credit union discovered that the hard way when its Corelation KeyStone investment left the mortgage team still retyping data by hand. Cloud-managed middleware closed that gap permanently, turning a manual bottleneck into an automated pipeline that improved speed, accuracy, compliance, and member experience across the board.
If your credit union, bank, or mortgage company is planning a core conversion or already running disconnected systems, the integration question isn't something you can push to next quarter. It's the difference between a technology upgrade and a technology transformation.
Corelation KeyStone and Calyx Path do not integrate natively out of the box. Credit unions connect them using cloud-managed middleware that maps data fields between both platforms, applies validation rules, and synchronizes loan records bi-directionally. The middleware translates between each system's data model so closed loans post automatically to the core without manual re-entry by staff.
Modern cores like KeyStone provide open APIs that make integration possible, but each vendor builds its API independently with different data models and field conventions. Someone still needs to build the translation layer that maps fields, validates data, handles exceptions, and maintains compatibility when either vendor releases updates. Without dedicated middleware, staff become the manual bridge between systems.
Research from McKinsey found that financial institutions running legacy or disconnected systems face operating costs up to 10 times higher than those with integrated platforms. Manual re-entry adds direct labor costs, error correction overhead, compliance remediation time, and delayed loan boarding that impacts member satisfaction. The cumulative cost grows with every loan closed through the manual process.
Credit unions should map every system that exchanges data with the core before conversion begins, including the LOS, digital banking platform, document management, and compliance reporting tools. For each connection, define the data fields, validation rules, sync frequency, and error handling requirements. Budget for middleware deployment alongside the core conversion rather than deferring it to a later phase.
Corelation signed 27 new credit unions in the first three quarters of 2025 alone, with conversions scheduled through 2026 and 2027. The largest signing was Wings Credit Union, a nearly $20 billion institution formed through a merger. Each of these credit unions will need to address LOS-to-core integration as part of their KeyStone deployment plan.