SEPA Compliance Middleware for High-Load Banking Pipelines
- Fintech
- Stream Processing
- Java
- Apache Kafka
- MongoDB
- Custom Banking Solutions
Overview of Our Client
Our client was a leading European banking institution, implementing SEPA payments and processing massive volumes of transfers every day. They operated under strict regulatory oversight and required live compliance checks to ensure that every transaction followed EU standards.
In this regard, the bank needed a high-throughput solution that could integrate into their core payment pipelines, as well as maintain full auditability, zero downtime, and the ability to scale horizontally during peak transaction periods.
Challenge
European banks normally face a unique combination of regulatory rigor and infrastructure pressure, especially when dealing with SEPA batch transfers. This way, the main challenges of the project included:
- Strict and evolving EU regulations requiring compliance checks for every single transfer.
- Extremely high throughput demands, reaching tens of thousands of SEPA requests per second (a "heavy load" even for the largest EU banks).
- The need for zero downtime processing, since any interruption in payment pipelines may result in massive financial penalties.
- Granular analysis of large batch files, where each transfer must be screened individually without losing batch-level context.
Main Goals
To fulfil all the requirements of the project, we defined the following goals:
- Automate ALR/AML compliance checks for instant SEPA payments.
- Categorize transactions into Accepted, Suspicious, and Manual Review flows.
- Integrate into bank core processing pipelines without introducing significant latency.
- Use sharding and horizontal scaling to handle peak loads (e.g., end-of-month salary runs).
- Provide reliable message storage and searchability for audit trails and regulatory reporting.
- Implement an active-active high availability architecture with no single point of failure.
Project Overview
We built a high-throughput financial middleware platform based on stream processing and distributed messaging. Apache Kafka handled reliable ingestion and queueing, allowing the system to process massive SEPA flows without message loss.
SEPA messages and processing results were stored in sharded MongoDB, which enabled horizontal scaling, high-concurrency writes, and fast lookups for auditing and regulatory reporting.
The infrastructure ran in an active-active configuration to eliminate single points of failure and ensure uninterrupted processing during outages or maintenance.
In on-premise deployments, the platform consistently processed tens of thousands of SEPA requests per second while maintaining strict compliance accuracy.
Solution
The result represented a high-availability financial middleware solution that could operate directly inside SEPA payment pipelines. It intercepted large incoming SEPA batches, split them into individual transfers, and performed automated regulatory checks on both transaction-level messages and the batch as a whole.
Each payment was classified as Accepted, Suspicious, or requiring Manual Review, guaranteeing that only compliant transactions were forwarded for execution. Risky or incomplete ones were blocked or routed for additional verification.
The platform was engineered for extreme throughput and resilience, supporting tens of thousands of SEPA requests per second in an active-active infrastructure with horizontally scalable storage and real-time stream processing.
Key Features
- Batch splitting and transaction-level parsing of SEPA files with context-aware re-assembly of validated transfers.
- Automated tri-state compliance classification into Accepted (immediate execution), Suspicious (blocked), and Manual (requires human intervention) transaction flows.
- Live message ingestion and queueing powered by Apache Kafka for lossless high-volume processing.
- Active-active high-availability infrastructure, eliminating single points of failure and ensuring full compliance with DORA (Digital Operational Resilience Act) standards for European banks.
- Low-latency compliance checks optimized for tens of thousands of SEPA requests per second in on-premise environments.
- Hybrid deployment model supporting both SaaS delivery and on-premise installations for banking-grade security requirements.
Technology Stack
To satisfy strict regulatory requirements and establish stable processing under extreme transaction loads, we selected the following technologies:
Backend
- Java
Message Broker
- Apache Kafka (high-load queuing and streaming)
Database
- MongoDB (sharded cluster)
Architecture
- Distributed active-active failover setup
Protocol Support
- SEPA / ISO 20022
Deployment
- SaaS and on-premise environments
Compliance Engine
- ALR / AML screening logic and rule processing
Core Team
- Fintech Systems Architect: Designed the SEPA processing model and ISO 20022 compliance approach.
- Distributed Systems Engineers: Implemented Kafka-based ingestion and tuned active-active synchronization.
- NoSQL Database Expert: Built MongoDB sharding strategy and optimized high-concurrency storage.
- Compliance & Regulatory Logic Developers: Developed ALR/AML rule sets and transaction classification logic.
- Infrastructure / SRE Engineers: Managed high-availability clusters for SaaS and on-premise deployments.
Results
The system enabled reliable and high-speed verification of SEPA transaction compliance at the scale required by major European banks. In particular, we achieved:
- Reduced regulatory risks by automatically checking each SEPA message for compliance with applicable EU requirements before execution. The architecture also supports integration with AI models for fraud-pattern detection, making the solution more future-proof.
- Improved operational efficiency by automating large-scale transaction filtering and limiting manual review to only truly suspicious cases.
- High performance under peak loads, providing stable processing of tens of thousands of SEPA requests per second in large banking environments.
- Better infrastructure resilience thanks to an active-active architecture, ensuring uninterrupted payment processing during maintenance and local hardware failures.