BNP Legacy Modernization

Context

BNP Paribas has a portfolio of 17 critical applications for its back-office operations. Jira, Confluence and Clarity had no obsolescence issues. The affected applications had Angular, Java and Spring Boot obsolescence requiring modernization to meet new performance, security and business agility challenges.

Challenge

The previous team had not followed architectural and code standards. Many applications were nearly impossible to take over due to interdependencies with common modules. Significant refactoring and rewriting had to be imposed. The previous PO and technical team left no documentation when departing and even hid some problems.

Approach

I structured the project into workstreams by application, with prioritization based on business criticality and technical debt. For each application, we defined a specific modernization plan: refactoring, re-platforming or rewriting. I facilitated agile ceremonies, wrote user stories in Gherkin format, and monitored quality and performance KPIs. Facilitator and coordinator role: I was the gateway between different teams (Architects, IOPS, Business).

Results

• Successful migration of 8 applications to Spring Boot/Angular/Java in 12 months
• 60% reduction in deployment time (CI/CD)
• Test coverage increased from 10% to 60% thanks to AI
• Zero major incidents during the transition period
• Continuing the momentum this year thanks to AI usage and implementation

Learnings

• Legacy modernization requires an incremental and pragmatic approach
• Business team involvement is key for continuous validation
• Using AI to carry out the various version upgrades helped us
• A migration involves many technical increments and cannot be done all at once. It's precision work, especially when applications are linked together
• Documentation and knowledge transfer are often underestimated