Australia’s largest customer-owned bank brings modern digital banking to small businesses
About Great Southern Bank
Great Southern Bank (GSB) is the country’s largest customer-owned bank serving customers across Australia. A member-first powerhouse, GSB has built its reputation on competitive products, personal service, and a mission to make life better for members.
The opportunity
GSB saw a clear gap in the SME market and decided to lead from the front. They set out to build a business-banking experience that felt modern, fast, and designed for real business needs with four key goals:
Business banking that empowers
Deliver genuine value to SMEs (from micro-businesses to mid-market) with intuitive, integrated banking solutions that delight.
Digitally native
Replace “somewhat digital” with truly end-to-end digital, giving business owners the same smooth experience they have come to expect from modern tech.
Modern lending
Bring business lending into the new era: with unsecured loans, term deposits, and vehicle finance that are easy to understand and quick to approve.
Operational efficiency that scales
Run the business bank with a small, high-performing team by leveraging automation, self-service, and AI-driven workflows.
The solution
GSB Business+ built and launched fast
Constantinople is the engine behind Business+, a fully digital platform that went live in March 2024 and launched nationally later that year. The platform is already exceeding expectations, building a strong deposit base and serving a brand new business segment. Built in partnership with Amazon Web Services, the platform runs on a cloud native architecture using Amazon Elastic Kubernetes Service (Amazon EKS) across multiple AWS Availability Zones. This allows GSB to launch and evolve new banking products rapidly without the constraints of legacy systems, ensuring always on availability for payments, lending, onboarding, and customer servicing.
Complex onboarding streamlined
Company owners, directors, and administrators of companies, partnerships, and trusts can now onboard and set permissions entirely online. AI optimises document processing and boosts straight-through-processing rates, turning what used to take days into minutes. Event driven processing built on AWS Lambda enables onboarding checks, identity verification, and compliance workflows to run in real time, allowing Business+ customers to open accounts and start banking almost instantly.
Comprehensive transactional capability
Business+ delivers everything SMEs need to run their finances in one place with multi-level approvals, batch payments, expense management, integrated invoicing, and native Xero and MYOB connectivity. The platform processes real time payment flows including NPP and Direct Entry events through an event driven architecture running on AWS. This allows transactions, approvals, and account activity to be processed instantly while maintaining full auditability and operational control.
Business lending that actually works
Working-capital facilities, equipment finance, and business term loans are now available digitally with ~10-minute credit decisions and seamless applications through to settlement. Real time data pipelines orchestrated through Amazon Managed Workflows for Apache Airflow feed lending models and credit policies, enabling automated decisioning while maintaining full governance and traceability.
Self-service that empowers bankers
GSB’s product, credit, and marketing teams can now configure products, run credit assessments, and access real-time portfolio reporting without manual processes or paper. The cloud native platform running on AWS enables continuous product configuration and deployment, allowing teams to launch new lending policies, pricing structures, and customer journeys without infrastructure changes.
Secure by design
Security and resilience are built into the platform using AWS native services including AWS Shield, AWS WAF, and Amazon GuardDuty, ensuring enterprise grade protection for every customer interaction.
The result
“Constantinople is transforming how banks operate, giving us an unmatched advantage to move fast and lead the market in digital banking for small businesses.”
Paul Lewis, CEO, Great Southern Bank
This isn’t just a tech upgrade, it’s a commercial transformation.
GSB Business+ proves member-owned banks can compete head-to-head with the majors and neobanks, delivering fast growth, operational leverage, and experiences that make customers proud to bank with a mutual.
