All topics
Start here introductory
- Core banking system architectureThe system of record for accounts, deposits and loans, and why its end-of-day cycle shapes everything around it.4 min read
- Payment system architectureSwitches, participants and settlement accounts, and the state machine that stops a payment being lost or made twice.5 min read
- API-first and open bankingLayered APIs from channel to core, what a gateway does, and how consented data sharing works through Account Aggregators.5 min read
Next intermediate
- Event-driven architectureEvents versus requests, logs and consumers, and the outbox pattern that stops events and data drifting apart.5 min read
- Data architectureTransaction and analytical stores, warehouses and lakes, streaming, and the lineage that regulatory reporting depends on.4 min read
- Legacy modernisationThe strangler fig, anti-corruption layers, data migration, parallel runs and why cutover is where projects fail.4 min read
- Security architectureDefence in depth: network zones, hardware security modules, just-in-time privileged access, detection and reporting duties.5 min read
Deeper advanced
- Multi-data-centre and disaster recoveryActive-passive and active-active, RPO and RTO, replication trade-offs, split-brain and what RBI expects from DR drills.4 min read
- Hybrid and multi-cloud deploymentWhere each workload runs, data localisation, outsourcing and exit planning, connectivity, identity and cost control.4 min read
How to read this section
Topics are grouped by how much background they assume. If you are new to banking systems, start with core banking system architecture, then payment system architecture. The advanced topics assume you know both.
Patterns described here are common across the industry. Where a page describes how a named organisation works, it cites a public source; everything else is labelled illustrative.
How the topics connect
How the architecture topics relate
Text description
The core banking system is at the centre. Payment systems post to it, API-first design exposes it, and event-driven design and data architecture carry its changes outward. Modernisation replaces it in stages. Security architecture protects the whole estate. Multi-data-centre design keeps it running, and hybrid cloud decides where each part runs.
- Payments to Core banking: posts to
- API-first to Event-driven
- Core banking to Event-driven: events
- Event-driven to Data
- Modernisation to Core banking: replaces
- Multi-DC and DR to Modernisation (optional or asynchronous)
- Hybrid cloud to Multi-DC and DR: where it runs
- Security to Hybrid cloud (optional or asynchronous)