Mirror-Ledger - redundancy, transparency, openness

What is Mirror-Ledger?

Mirror-Ledger is a special additional layer (middleware) built into the banking infrastructure that duplicates all incoming, outgoing and internal payment documents. In essence, it is a separate transaction register (ledger), which forms a complete copy of all transactions outside the Core Banking System. This approach allows the bank to have an independent channel for audit, analytics and operational management even in case of failures in the Core Banking System.

Key Features

• Complete transaction duplication. Mirror-Ledger captures all payment orders - from the smallest to the most critical transactions - and stores them in a separate register. This allows you to get an accurate picture of cash flow at any time.

• Non-invasive integration. Mirror-Ledger layer is installed between the client interface and the main core of the system, without disturbing the current logic of the bank. The existing ABS works unchanged, while the new layer collects and transmits data discreetly.

• Vendor-independence. Thanks to the independent architecture, the new layer allows you to connect modules from any vendor or develop your own solutions. This reduces the bank's dependence on a single vendor and opens up opportunities for rapid evolution of functionality.

• Hybrid operation with the main system. Mirror-Ledger functions in parallel with the existing core as a hybrid unit (analogous to Toyota Prius with two types of drives). In the event of problems in the core system, the redundant registry ensures continuity of operations, and data is synchronized both ways during normal operation.

• Reliable data source for auditing and analytics. The complete transaction register becomes a “black box” against which auditors and internal controllers can quickly verify the validity of entries. This greatly simplifies reporting and increases transparency of financial flows.

• A platform for the development of new services. Thanks to its modular architecture Mirror-Ledger is a base for quick introduction of additional functions - be it BNPL, new forms of crediting, loyalty programs or other innovative services. New modules are easily “hinged” on the mirror layer, and bidirectional synchronization guarantees data integrity.

Benefits to the bank

• Resilience and continuity of operations. In the event of a failure in the main core, Mirror-Ledger is able to temporarily take over critical functions, ensuring uninterrupted customer service.
• Flexibility for modernization. Absence of necessity to interfere with the main software allows the bank to adapt and develop new services without large-scale rebuilds, avoiding temporary downtime.
• Reduction of operational risks. A fully redundant transaction register ensures high audit accuracy and control over financial flows, reducing the risk of error and fraud.
• No technology lock-in. The ability to connect modules from different vendors or develop in-house solutions helps the bank to avoid vendor lock-in and choose the most efficient solutions.
• Cost savings. Using Mirror-Ledger helps to gradually replace outdated and expensive cores by migrating only 98% of core functions, while the remaining minor processes can be integrated through new modules.

Taken together, this design reflects the logic of a “digital twin”. Mirror routes commands from different participants (customers, internal users, external services) to Core Banking and vice versa, while preserving transactions, simplifying integration and adding flexibility for further improvements without deep intervention in the bank's core system.

Logic of Interaction

1. Client (via digital channels) sends commands/orders to Mirror.
2. Pre-co-processing validates and structures these commands, writes them to co-Ledger DB and Write-Side DB.
3. The Read-Side DB synchronizes with the “Write-Side”, preparing data for fast fetching and query responses.
4. Mirror has a common mechanism to:
   • Accept write commands (create, modify transactions) and send them to Core Banking or RTGS.
   • Return the result to the user via “Answering all Queries / Responding to Commands”.
   • Give Internal Users convenient search and reporting tools without directly interfering with the core.
5. Core Banking System, RTGS and New External Services operate “business as usual”; Mirror acts as a proxy and “mirror” of all operations, allowing functionality to be extended without breaking the core system.

The key benefits of the system

• Minimal impact on Core Banking: Core Banking remains “as is” and all new services are connected to Mirror.
• High reliability and transparency: individual bases (co-Ledger, Write-Side, Read-Side) maintain an exhaustive transaction log and are not directly dependent on the stability of the core system.
• Flexible scalability: New applications (New External Services, New extended features) can be easily added to handle growing transaction volumes.
• Comfortable work for bank employees: Internal User gets advanced analytics and reporting from Read-Side DB without loading the core.
• Support for modern technologies: if necessary, modules using NLP, LLM or other tools are added, facilitating interaction with clients and data processing.

Thus, the system diagram shows how Mirror, consisting of several databases (Write/Read) and command processing services, becomes a universal integration layer and a “mirror” for core banking processes.

Mirror-Ledger

Mirror-Ledger is a strategically important solution that enables a bank to move beyond the traditional, often outdated Core Banking System. With full transaction replication, hybrid architecture and independent integration, the new layer ensures continuity of operations, increases transparency and creates a platform for further digital transformation of banking services.

The innovative Mirror-Ledger concept not only protects the bank from failures and errors, but also significantly accelerates the implementation of new functional modules, opening up new opportunities for revenue growth and improved customer experience.

Mirror-Ledger - резервирование, прозрачность, открытость. Proposal for a working session on mirror data warehouse and reporting (en) 000 SoftClub