Banking has become an always-on business. Customers expect instant payments, accurate balances, and continuous access to financial services, while banks face increasingly demanding resilience and regulatory requirements. Temenos and Cockroach Labs are addressing these demands by running Temenos Core on CockroachDB, combining cloud-native core banking capabilities with a distributed SQL database designed for resilient, scalable transaction processing.
Yet many institutions still depend on decades-old core infrastructure built around batch processing and vertically scaled databases. This makes core banking modernization increasingly important for supporting real-time transactions, continuous availability, and distributed operations.
Why legacy core banking infrastructure is falling behind 
Many banks are asking for infrastructure designed for an earlier era to support always-on transactions, modern regulatory requirements, and increasingly distributed operations. The consequences increasingly appear in database resilience and availability, technology costs, and the ability to support real-time banking.
This pressure to modernize core banking infrastructure is no longer theoretical. UK banks experienced 158 outages between January 2023 and February 2025, totaling 33 days of downtime. That adds up to over a month of disrupted banking services.
At the same time, aging core systems consume technology budgets that could otherwise fund innovation. Batch-oriented architectures also make it harder to deliver the real-time processing customers expect, while regulations such as the EU Digital Operational Resilience Act (DORA) raise the bar for operational resilience.
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What core banking actually does, and why the database matters
“A core banking system is the operational system of record for customer accounts, balances, transactions, and financial events,” says David Joy, Technical Director | AI, Ecosystem & Partnerships. “It must support workloads ranging from real-time transaction processing to interest accruals, Close of Business (COB), multi-currency and multi-entity operations, and integrations with payments, fraud, and regulatory systems.”
“That makes the underlying database a foundational part of core banking system architecture,” Joy continues. “Its scalability affects transaction capacity, its availability affects whether customers can transact, and its consistency affects the accuracy of the bank's books.”
How T24 evolved into Temenos Core
Temenos Core is a cloud-native, microservices-based core banking platform designed for continuous innovation and upgradability. It evolved from the platform previously known as T24 and Temenos Transact and today serves more than 1,000 financial institutions across 150+ countries.
Key capabilities include:
High-volume transaction processing: Manages the transaction lifecycle from booking through settlement, including the High Volume Transaction (HVT) Merge Service for efficiently processing large volumes of postings.
Multi-currency and multi-entity operations: Supports operations across 20+ currencies, multiple legal entities, cross-border booking, and back-valued transactions up to 10 years.
Close of Business processing: Runs parallel end-of-day processing for account balancing, interest accruals, and preparation for the next business day.
Open, extensible architecture: Uses open APIs, the Temenos Extensibility Framework (TEF), and the Java-based TAFJ runtime to support integration, extensibility, and cloud-native deployment.
Why CockroachDB for Temenos Core?
“Scaling a modern core banking platform has many requirements,” explains Joy. “The database layer must support growing transaction volumes, continuous availability, distributed deployments, and strong transactional consistency without relying on manual sharding or complex failover architectures.”
“CockroachDB is a distributed SQL database built on a transactional, strongly consistent key-value store, inspired by Google Spanner and F1,” Joy says. “It combines horizontal scale and automated resilience with serializable ACID transactions and a familiar SQL interface, providing a distributed database foundation for Temenos Core.”
Key CockroachDB capabilities that support Temenos Core include:
Horizontal scalability without manual sharding: CockroachDB supports database scalability by allowing nodes to be added as transaction volumes grow without manual re-sharding or schema redesign.
High availability by design: CockroachDB provides a high availability database architecture by replicating data across nodes using the Raft consensus algorithm and automatically recovering from infrastructure failures without requiring manual failover.
Serializable ACID transactions: CockroachDB provides serializable isolation across the distributed cluster, maintaining transactional consistency as workloads span nodes.
Flexible deployment: CockroachDB can run on-premises on Kubernetes, in Cockroach Cloud on Azure or AWS, or as part of a hybrid architecture.
Data sovereignty controls: Geo-partitioning capabilities can place data in specific regions to support data residency requirements while maintaining distributed operations.
PostgreSQL compatibility: CockroachDB supports the PostgreSQL wire protocol and the majority of PostgreSQL syntax. Temenos Core connects through a PostgreSQL-flavored JDBC configuration in TAFJ, reducing integration complexity.
Proven financial services adoption: Financial services organizations, including Global Payments and Groww, use CockroachDB for critical transactional workloads.
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How Temenos Core and CockroachDB work together
Temenos Core and CockroachDB address complementary layers of the banking stack: Temenos provides the core banking application capabilities, while CockroachDB provides a distributed transactional database foundation for scale, resilience, and consistency.
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“For existing Temenos Core customers, CockroachDB provides a path to database modernization by addressing database scalability and availability requirements without replacing the application's business logic,” says Nanda Badrappan, Deputy Chief Technology Officer for Temenos. “TAFJ's CockroachDB configuration provides the integration path between the two platforms.”
Temenos Core on CockroachDB: functionality and performance validation
Joint testing demonstrated that Temenos Core on CockroachDB could support the tested multi-currency, high-volume, and Close of Business (COB) workloads while scaling near-linearly as resources were added in the tested configurations. Temenos and Cockroach Labs jointly validated Temenos Core on CockroachDB v25.4.2 across on-premises Kubernetes environments and Microsoft Azure. The testing processed 2 million transactions across 20,000 accounts, including approximately 750,000 transactions against a single high-volume account.
The validation covered:
Multi-currency transaction processing: Transactions across 20 currencies, including back-valued transactions spanning up to 10 years.
High-volume processing: The HVT Merge Service ran concurrently with live online transaction workloads without degrading online transaction performance.
Close of Business: COB processing completed successfully following active transaction workloads without interruption or performance degradation.
Horizontal and vertical scalability: Both increasing resources per node and adding application pods and database nodes were evaluated using a realistic Tier 1 bank transaction mix. Near-linear scaling was observed in the tested configurations as resources were added.
In the cloud environment, transaction throughput increased as application pods and database nodes were added while CPU utilization and memory profiles remained stable across the cluster. In the on-premises configuration, the HVT Merge Service completed concurrently with online transaction workloads, demonstrating the ability to run mixed workload types without mutual interference. COB processing also completed successfully across test runs, validating operational integrity from transaction booking through day-end settlement.
The integration required targeted configuration across TAFJ, CockroachDB, and the application layer, including transaction isolation settings, zone configurations for high-contention tables, and messaging-layer optimizations. These configuration parameters have been documented as part of the joint reference architecture.
Detailed benchmarking results including hardware specifications, tuning parameters, scalability results, and monitoring charts are available to prospective customers through the joint Temenos–Cockroach Labs engagement team.
Looking ahead
“This validation program marks the beginning of a deeper integration roadmap,” Badrappan observes. “Temenos and Cockroach Labs plan to extend the joint work through larger-scale performance testing, reference architectures for on-premises and cloud deployments, migration tooling for existing Temenos customers, multi-region deployment patterns for data sovereignty requirements, and deeper integration across the Temenos suite.”
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See how the validated Temenos Core and CockroachDB architecture could support your core banking modernization requirements.
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2026 Temenos Headquarters SA and Cockroach Labs, Inc. This document is intended for informational purposes. Performance results are environment-specific and may vary based on configuration, workload, and infrastructure.
