Migrating to a new core banking system is one of the most critical transformations a financial institution can undertake. This blog provides a step-by-step core banking migration testing checklist, covering data validation, reconciliation, integration testing, performance validation, security compliance, and go-live readiness. It helps banks reduce risk, avoid financial discrepancies, and ensure a smooth transition with zero customer impact.

Introduction

Core banking migration involves transferring customer accounts, loans, transactions, balances, and configurations from a legacy system to a new Core Banking Solution (CBS) such as:

• Finacle
• Oracle FLEXCUBE
• Temenos T24

That’s why having a detailed migration testing checklist is non-negotiable.

Pre-Migration Testing Checklist

Requirements Validation

• Confirm migration scope (Retail / Corporate / Treasury)
• Validate data mapping documents
• Freeze functional requirements

Environment Readiness

• Setup staging & migration environment
• Mask sensitive production data
• Validate infrastructure & access controls

Migration Strategy Validation

• Big bang vs phased migration
• Cutover window planning
• Rollback strategy defined

Data Migration Testing Checklist

Data migration is the heart of core banking transformation.

Data Mapping Validation

• Source to target field mapping validation
• Data type compatibility check
• Mandatory field validation

Data Integrity Testing

• Customer ID validation
• Account number accuracy
• Product code consistency
• Currency mapping accuracy

Data Reconciliation Testing

• Pre-migration vs post-migration balances
• Loan outstanding reconciliation
• Interest accrued validation
• GL balance matching

Transaction Validation

• Historical transaction consistency
• Date/time accuracy
• Duplicate record detection

Integration Testing Checklist

Core banking systems integrate with:

• Payment gateways
• ATM switch
• CRM
• Internet & mobile banking
• Regulatory reporting systems

API Validation

• Real-time API response validation
• Timeout & retry mechanism testing

End-to-End Flow Testing

Example flow:
Customer → Mobile Banking → Core System → GL Update → SMS Notification

Every step must be validated.

Performance & Load Testing Checklist

Migration often increases load temporarily.

Volume Testing

• Peak transaction simulation
• Bulk transaction posting

Stress Testing

• High concurrent user validation
• Failover scenario testing

Batch Processing Testing

• EOD (End of Day)
• EOM (End of Month)
• Interest posting cycles

Security & Compliance Testing

Banks operate in highly regulated environments.

Role-Based Access Validation

• User role migration accuracy
• Privilege escalation testing

Audit Trail Validation

• Log consistency
• Regulatory compliance checks

Data Encryption Validation

• Data at rest encryption
• Data in transit validation

User Acceptance Testing (UAT) Checklist

Business users must validate:

• Account opening
• Loan processing
• Fund transfers
• FD/RD creation
• Charges & fees calculation
• Interest calculation

Include branch users, operations team, and compliance officers in UAT.

Go-Live Readiness Checklist

Before production deployment:

• Final reconciliation signed off
• Cutover checklist completed
• Backup validation completed
• Rollback plan approved
• Stakeholder sign-off documented

Post-Migration Validation Checklist

After go-live:

Monitor transaction failures
Validate daily reconciliations
Monitor performance KPIs
Validate customer complaints

First 30 days are critical.

Common Migration Risks

Risk	Impact
Incorrect data mapping	Financial losses
Incomplete migration	Customer impact
Poor reconciliation	Regulatory penalties
Performance issues	Reputation damage

Best Practices for Zero-Defect Migration

✅ Run multiple dry runs
✅ Automate reconciliation
✅ Maintain audit logs
✅ Use production-like environments
✅ Engage business users early
✅ Use automated regression suites

Since you work in test automation strategy campaigns, this topic is highly aligned for positioning your solution as a migration testing partner.

FAQs

Conclusion

Core banking migration is high-risk but manageable with a structured testing checklist. By focusing on:

• Data accuracy
• Reconciliation
• Integration validation
• Performance stability
• Compliance assurance

Banks can achieve zero-disruption go-live and protect customer trust.