Modernisation without a feature freeze

Stepwise migration of a monolith to an event-driven architecture while the roadmap kept shipping.

A B2B SaaS provider faced the classic choice: keep stretching the grown monolith, or sacrifice a year of roadmap for the big rebuild. Neither was acceptable.

Starting point: Quarterly releases, long regression cycles, and every larger change touched code nobody wanted to own. New features and technical recovery competed for the same people.

Approach: An event-driven target architecture, reached through a stepwise strangler migration instead of a big-bang rewrite. Foundation first: a CI/CD pipeline, a test strategy and short-lived branches, so every step was safely shippable. Then the critical domains were extracted one by one, each with a clean cut and a way back.

Outcome: Weekly releases instead of quarterly, the riskiest domains run as separate services, and the roadmap kept delivering through the entire migration. The team understands and owns the new architecture.

• Industry: B2B SaaS
• Duration: 9 months, alongside the roadmap
• Services: Software Architecture Consulting, Software Implementation, CI/CD & Engineering Process Setup