How ING Bank Manages 2,000 Microservices With Service Mesh

ING Bank has spent nine years evolving a service mesh to manage over 2,000 microservices across a hybrid multi-cloud environment. Key lessons from their journey include: standardizing cross-cutting concerns like mTLS, authentication, and SLA enforcement rather than having each team reimplement them; building on familiar technology (Java framework plus sidecar proxy) instead of adopting off-the-shelf tools wholesale; using OpenAPI and an internal API marketplace for authoritative service discovery tied to JWT-based authorization; opting for a pull-based control plane and client-side load balancing to avoid central bottlenecks at scale; and investing in enabler teams, bi-weekly knowledge-sharing sessions, and a community of practice to drive organizational adoption. Today, 1,700 workloads across 2,200 applications and 850 teams use the platform in production.