01
System & API Design
We design distributed systems, APIs and platform boundaries for financial environments where reliability, traceability, data consistency and long-term maintainability matter.
Quercore Systems
System design, modernization and integration delivery for critical financial platforms
Quercore Systems helps banks, lenders, fintech platforms and software vendors design, modernize and deliver critical financial systems where architecture decisions carry real operational and commercial weight.
Senior-only engineering. System and API design. Integration-heavy delivery. Based in Krakow, Poland, supporting clients and delivery partners across European and international financial technology markets.
What we do
We help financial platforms move faster in environments where change is expensive, systems are hard to evolve, and technical decisions carry commercial and operational weight.
02
Architecture Audit
A focused review of your platform, integration landscape and delivery bottlenecks, with clear recommendations for what to fix first.
03
Modernization Sprint
A hands-on engagement to reduce technical risk, stabilize a difficult area, or prove a safer path forward without a full rewrite.
04
Senior Team Extension
A senior engineering unit that plugs into your roadmap where architecture depth, backend strength and integration experience matter most.
How we work
Senior judgment, practical AI support and controlled delivery
We use AI as part of our daily engineering workflow to accelerate research, code analysis, documentation, test planning and technical review. It helps us move faster through complex information, but it does not replace expert responsibility. Every recommendation, design decision and delivery output is reviewed through the lens of senior engineering experience, system context and production risk.
AI-assisted. Expert-led. Production-aware.
01
AI-assisted analysis
We use AI to speed up research, compare options, review large code areas, summarize documentation and identify questions that need deeper technical validation.
02
Expert-led decisions
AI helps with analysis, but architecture decisions stay with experienced engineers who understand domain behaviour, production risk and delivery constraints.
03
Practical delivery support
We use AI to improve documentation, test thinking, review preparation and implementation planning, while keeping responsibility, context and judgment with the team.
Where we are strongest
We do our best work in live, business-critical platforms that are complex, integration-heavy and difficult to change.
01
System & API design
Designing APIs, service boundaries, workflows, integration contracts and distributed platform components that engineering teams can build and operate.
02
Legacy modernization
Untangling monoliths, reducing coupling and creating a realistic path toward cleaner architecture.
03
Complex financial integrations
Designing and delivering resilient integrations across payments, KYC, credit, servicing, decisioning and operational workflows.
04
Critical platform delivery
Working in environments where reliability, traceability, data integrity and controlled change matter.
05
Backend architecture
Improving structure, ownership, observability and maintainability in systems under constant business pressure.
Selected integration domains
Our experience spans multiple layers of financial platform integration, from customer onboarding and verification to servicing, payments and external decisioning.
- Payments and merchant processing
- Credit, fraud and identity
- Open Banking and account verification
- Lending and servicing platforms
- Property and valuation data
- Reference data and public registries
Selected platform and gateway experience
Our experience includes integration work across multiple layers of financial platforms, from payments and account verification to credit, fraud, servicing and valuation workflows.
Payments and merchant processing
- Worldpay
- Barclays ePDQ
- PAY360
- Mastercard hosted payments
- CardEasy
Account verification and Open Banking
- SurePay
- Yapily
- ClearBank
- Bank Wizard
- SWIFT / BIC support
Credit, fraud, identity and decisioning
- Experian
- Equifax
- CrossCore
- Hunter
- FICO
- IdentityHub
- SIRA
Lending, servicing and underwriting
- Pepper
- Phoebus
- HML / Computershare
- Target Group
- Acenden
- Rothesay
Property and valuation
- Landmark SPN+
- Hometrack
- Rightmove
- Kamma
- WhenFresh / PriceHubble
Reference data and registries
- Companies House
- Central Credit Register Ireland
Representative experience is shown for context only. References describe delivery familiarity across platform work, not public client endorsements or formal partnerships.
Why clients bring us in
Why clients bring us in
Clients usually speak to us when delivery has slowed down, integration complexity is growing, and the platform feels harder to change. We help restore clarity, reduce technical friction and create a safer path forward.
- Senior-only delivery model
- Fast onboarding into difficult systems
- Comfortable with legacy code and operationally sensitive workflows
- Strong backend and integration capability
- Discreet and white-label friendly
Proof
Senior support for live, high-risk platform work
We are typically brought into platform areas where third-party dependencies are dense, change is commercially sensitive, and architecture decisions carry operational consequences. The work is often integration-heavy, operationally sensitive and already under delivery pressure.
- Senior-only delivery for architecture-heavy work
- Experience across payments, verification, bureau, fraud, servicing and underwriting integrations
- Comfortable in live environments where reliability, traceability and controlled change matter
- Strong fit for modernization without disruptive rewrite programmes
- Architecture and backend judgment under delivery pressure
- Discreet and white-label capable where needed
Insights
Latest insights
Published articles and practical notes on system design, modernization, integration risk and architecture under delivery pressure.
System & API Design
Designing APIs and System Boundaries for Critical Financial Platforms
Architecture Audit
When architecture audits create real delivery value
Confidential discussion
Start with a confidential conversation
If your platform needs clearer system boundaries, safer API design, difficult integrations or modernization progress, we would be happy to discuss it.