Toss Payments Server Platform team manages thousands of API and batch servers through a unified configuration system. They evolved from copy-paste YAML configurations to an overlay architecture with template patterns for API servers, enabling layered configuration inheritance (global, cluster, phase levels) with dynamic value injection. For batch servers processing billions in daily settlements, they built a Job-DSL adapter wrapper around Jenkins and implemented dynamic provisioning infrastructure that allocates dedicated nodes on-demand. Both systems emphasize testable, declarative configurations that can evolve with requirements, reducing operational overhead and enabling rapid infrastructure changes like JDK version upgrades across hundreds of servers.