Custom Software Development · Fintech & Banking

Custom Fintech Software Development

Back-office financial infrastructure built around legacy core banking systems, payment rail routing, and reconciliation that catches a break the same day.

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How we work

Behind a bank's or credit union's customer-facing products sits infrastructure that rarely gets a redesign: a core banking system running on decades-old batch file interfaces, payment rails that each settle and reverse transactions differently, and a reconciliation process that only catches a discrepancy weeks later during an audit if nobody built something better. This is the software that has to be right every single day, not the software anyone shows a customer.

We build the middleware that bridges legacy core banking batch files to modern APIs, payment orchestration engines that route each transaction across ACH, wire, RTP, or FedNow based on cost and counterparty support, and BSA/AML transaction monitoring that flags suspicious activity without burying a compliance team in false positives. Regulatory reporting, Call Reports, Reg E error resolution, Reg CC funds availability, pulls from whichever systems hold the underlying data, on the schedule regulators actually require rather than a best-effort export.

The common requirement across all of it is a same-day reconciliation discipline: a ledger break between the core system and a downstream process needs to surface before the next business day, not weeks later when the gap has already compounded.

The problem

What makes fintech & banking projects different

Legacy core banking systems expose batch files, not APIs
Many core banking platforms still run on mainframe architecture with narrow, often COBOL-era batch file interfaces, and connecting them to a modern payment or reporting system requires custom middleware rather than a standard API integration.
Payment orchestration has to route by rail-specific rules
ACH, wire, RTP, and FedNow each have different cost, speed, and reversal semantics, and an orchestration layer needs rail-specific failure handling built in rather than treating every payment method the same way.
BSA/AML monitoring drowns in false positives without tuning
Transaction monitoring rules tuned too broadly generate more flagged activity than a compliance team can actually review, which defeats the purpose of monitoring just as thoroughly as rules tuned too narrowly to catch real risk.
Regulatory reporting pulls from systems that don't agree
Call Reports and other regulatory filings require pulling consistent data from core banking, payments, and general ledger systems on a strict schedule, and any disagreement between those sources becomes a reporting error with real regulatory consequences.
Reconciliation breaks compound if they aren't caught same-day
A discrepancy between the core ledger and a downstream system that isn't caught until an audit weeks later is far harder to trace back to its cause than one flagged the same business day it occurred.

Scope

Features we commonly build

Core banking middleware
A translation layer bridging legacy batch file interfaces from core banking platforms to modern APIs, without requiring a core system replacement.
Payment orchestration engine
Transaction routing across ACH, wire, RTP, and FedNow rails based on cost, speed, and counterparty support, with rail-specific failure and reversal handling.
BSA/AML transaction monitoring
Configurable rule sets for suspicious activity detection, with a case management queue tuned to surface real risk without overwhelming compliance staff.
Automated regulatory reporting
Call Report, Reg E, and Reg CC data assembled automatically from core banking and payment systems on the required filing schedule.
Daily reconciliation engine
Same-day comparison between the core ledger and downstream payment and reporting systems, flagging breaks before they compound.
Real-time payment status tracking
Cross-rail visibility into payment status, from initiation through settlement, replacing manual status checks across separate payment consoles.
Treasury and liquidity dashboards
Consolidated liquidity position across accounts and rails, giving treasury staff one view instead of reconciling several system exports by hand.
Audit logging across transaction touchpoints
A traceable record of every system a transaction passed through, supporting both internal audit and regulatory examination requests.

Compliance and standards

BSA/AML
Reg E
Reg CC
OFAC sanctions screening
SOC 2

Common integrations

FedNow
The Clearing House RTP network
Nacha ACH network
Fiserv
FIS
Jack Henry

Approach

How we run these projects

We start by mapping the institution's core banking system's actual batch file formats and schedules, since that determines what the middleware layer has to bridge before any payment orchestration or reporting logic gets designed. Rail-specific routing rules get validated against the institution's actual cost and counterparty data.

Reconciliation logic is built and tested against a set of real historical transactions with known breaks, comparing the system's output to what actually happened, before it runs against live data. BSA/AML rule tuning happens iteratively against the institution's actual transaction volume, since a rule set imported from a different institution's risk profile rarely fits without adjustment.

Typical stack

Systems in this space

FAQ

Frequently asked questions

How do you integrate custom software with a legacy mainframe core banking system?

We build a middleware layer that reads and writes the core system's existing batch file formats, translating them into APIs that modern payment and reporting systems can consume, rather than requiring a core banking replacement to get there.

Can a payment orchestration engine choose between ACH, wire, RTP, and FedNow automatically?

Yes, routing logic can select a rail based on cost, speed, and whether the receiving institution supports it, with rail-specific handling for failures and reversals built in since each rail behaves differently when something goes wrong.

How do you reduce false positives in BSA/AML transaction monitoring?

Rule thresholds get tuned iteratively against the institution's actual transaction volume and typical patterns, rather than deployed at vendor defaults, and flagged activity routes into a case management queue sized to what compliance staff can realistically review.

How long does it take to build a regulatory reporting system for Call Reports?

A focused system pulling data from core banking and payment systems for one or two report types typically takes a few months, with additional report types and data source reconciliation extending the timeline based on how consistent the underlying systems already are.

Does daily reconciliation catch ledger breaks before they compound?

That's the design goal: a same-day comparison between the core ledger and downstream systems flags a discrepancy the day it occurs, rather than during a periodic audit weeks or months later when tracing the root cause is far harder.

Do you support real-time payments via FedNow or RTP?

Yes, we build payment orchestration to route eligible transactions through FedNow or The Clearing House's RTP network where the institution and counterparty both support it, alongside traditional ACH and wire rails for everything else.