How ISO 20022, Open Banking, and API Architecture Work Together

  1. Executive Summary
  2. Introduction
  3. ISO 20022: Beyond a Messaging Standard
    1. Understanding ISO 20022
    2. ISO 20022 as an Architectural Pattern
    3. The Three-Layer Model of ISO 20022
  4. ISO 20022 and Open Banking
    1. Defining Open Banking
    2. ISO 20022’s Role in Open Banking
  5. API Architecture in Open Banking
    1. The Importance of APIs
    2. Aligning ISO 20022 with API Architectures
  6. Platform-as-a-Service (PaaS) and Microservices
    1. The Shift to PaaS
  7. Microservices Architecture
  8. Synergistic Integration: A Case Study
    1. Implementing a New Payment Processing System

Executive Summary

The financial services industry is undergoing a transformation, driven by the convergence of consumer data rights (CDR,PSD2, OBIE, Dodd-Frank Act ),advanced technologies and evolving customer expectations. Central to this evolution are ISO 20022, Open Banking, API Architecture, and Platform-as-a-Service (PaaS). This blog post explores how these components synergistically form the ultimate banking technology stack, fostering innovation, enhancing interoperability, and delivering superior customer experiences.

In the journey of digital transformation we deal with legacy systems. These being both people and tech – how people work and the technology used to build and deliver software. The integration of ISO 20022, Open Banking principles, API-centric architectures, and PaaS models represents a strategic approach to achieving this modernization. This paper delves into each component’s role and elucidates their collective impact on the banking sector.

ISO 20022: Beyond a Messaging Standard

Understanding ISO 20022

ISO 20022 is an international standard for electronic data interchange between financial institutions. It provides a common platform for developing messages using:

  • A Modelling Methodology: Captures financial business processes and transactions in a syntax-independent manner.
  • A Central Dictionary: Defines business items used in financial communications.
  • Design Rules: Convert message models into specific syntax, such as XML or ASN.1 schemas.

This comprehensive framework facilitates consistent and rich data exchange across various financial services domains, including payments, securities, trade services, cards, and foreign exchange.

ISO 20022 as an Architectural Pattern

While often perceived merely as a messaging standard, ISO 20022 embodies an architectural pattern that influences the design and integration of banking systems. Its structured approach to modelling business processes and data elements aligns seamlessly with modern architectural paradigms, such as service-oriented architecture (SOA) and microservices. By providing a unified data dictionary and modelling methodology, ISO 20022 enables financial institutions to design interoperable and modular systems, reducing complexity and enhancing agility.

The Three-Layer Model of ISO 20022

ISO 20022 is structured into a three-layer model:

  1. Business Processes and Concepts: Defines the activities, roles, and actors involved in financial transactions, establishing a common understanding across the industry.
  2. Logical Data Models and Flows: Specifies data elements and their interrelationships, ensuring consistency and interoperability in data exchange.
  3. Syntax: Deals with the physical representation of data, such as XML or JSON schemas, facilitating seamless communication between disparate systems.

This layered approach allows financial institutions to separate business logic from technical implementation, promoting flexibility and adaptability in system design.

ISO 20022 and Open Banking

Defining Open Banking

Open Banking refers to the practice of allowing third-party developers to access financial institutions’ data and services through Application Programming Interfaces (APIs). This paradigm shift aims to foster innovation, enhance customer experiences, and promote competition within the financial services industry.

ISO 20022’s Role in Open Banking

ISO 20022’s standardized data models and messaging protocols are instrumental in the Open Banking ecosystem. By providing a common language for financial data exchange, ISO 20022 ensures secure and efficient data sharing between banks and third-party providers. This standardization is crucial for achieving interoperability and compliance with regulatory requirements, such as the Revised Payment Services Directive (PSD2) in Europe.

API Architecture in Open Banking

The Importance of APIs

Application Programming Interfaces (APIs) are the conduits through which Open Banking operates. They enable third-party developers to access financial services and data, fostering innovation and competition. APIs allow banks to offer new services, such as account aggregation, payment initiation, and personalized financial management tools, enhancing customer engagement and satisfaction.

Aligning ISO 20022 with API Architectures

The alignment of ISO 20022 with API architectures ensures that data exchanged via APIs adheres to a standardized format, enhancing interoperability and reducing integration complexities. This synergy allows financial institutions to develop modular and reusable services, accelerating time-to-market for new offerings and facilitating compliance with regulatory mandates. citeturn0search5

Platform-as-a-Service (PaaS) and Microservices

The Shift to PaaS

Platform-as-a-Service (PaaS) allows banks to develop, run, and manage applications without the complexity of building and maintaining the underlying infrastructure. This cloud-based approach offers scalability, flexibility, and cost-effectiveness, enabling financial institutions to respond swiftly to market changes and customer demands.

Microservices Architecture

Complementing PaaS, microservices architecture involves decomposing applications into loosely coupled, independently deployable services. This modular approach aligns with ISO 20022’s principles by allowing financial institutions to develop and deploy specific business functionalities rapidly, facilitating continuous improvement and innovation. citeturn0search4.

The reusable services mentioned earlier are captured in micro-services. The legacy system problem is then solved by wrapping the existing code with microservices. If there is one thing you don’t want to do is start messing with code that works. As to replacing systems, when was the last time your replacement project delivered the desired outcomes on time and in budget.

Synergistic Integration: A Case Study

Implementing a New Payment Processing System

Consider a bank implementing a new payment processing system:

  • ISO 20022: Provides the standardized messaging framework, ensuring consistent data representation and communication.
  • Open Banking: Allows the bank to expose payment services to third-party providers via secure APIs, enabling customers to initiate payments through various platforms.
  • API Architecture: Ensures that these services are accessible and interoperable, adhering to industry standards. Examples are Open API (Swagger), Open Banking (BIAN™). And don’t forget the ISO 20022 standard.
  • PaaS: Offers the scalable infrastructure to host these services, allowing the bank to focus on application development without worrying about underlying hardware.
  • Microservices: Enable the bank to develop each component of the payment system as an independent

This blog post is curated by a Human-in-the-Loop using ChatGPT 4o and Perplexity. We built this as a course Before Gen-AI using Google and ISO 20022 for Dummies. Took a long time. Perplexity tapped into 40 sources and ChatGPT 20. That is the same measure of efficiency and effectiveness we are finding in Dev, Ops and QA.  

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