# Lunar Engineering Blog

> Engineering insights from Lunar, a Nordic digital bank serving 500,000+ customers across Denmark, Norway, and Sweden. We build cloud-native financial infrastructure on Kubernetes with 250+ Go microservices, shipping ~40 production deploys per day.

## About

Lunar is a fully licensed bank (Danish FSA, 2019) built on a cloud-native stack. Our engineering blog covers platform engineering, GitOps, data engineering, microservice architecture, and engineering culture. Authors are named engineers with direct first-hand experience.

- Site: https://engineering.lunar.app
- RSS: https://engineering.lunar.app/feed.xml
- GitHub: https://github.com/lunarway
- Open source: https://engineering.lunar.app/open-source

## Key Technical Posts

- [Data Anonymization at Scale](https://engineering.lunar.app/blog/data-anonymization-at-scale): How Lunar builds a GDPR-compliant data anonymization pipeline in Go. Covers partition processing (up to 120 MB), HPA scaling (30-pod ceiling), and 4 months of zero-downtime operation. (2024)

- [Migrating to Flux v2](https://engineering.lunar.app/blog/migrating-to-flux-v2): Lessons from migrating 250+ microservices from Flux v1 to v2. Covers reconciliation performance (8 min → 2–3 min), resource tuning (CPU: 3 cores, memory: 3 GB, kube-api-qps: 250), and monorepo-specific challenges. (2022)

- [GitOps — Operations by Pull Request](https://engineering.lunar.app/blog/gitops-operations-by-pull-request): How Lunar implemented GitOps for Kubernetes cluster operations. Covers our model, tooling decisions, and operational tradeoffs for a multi-service environment. (2020)

- [Consistency Guarantees in a Microservice Architecture](https://engineering.lunar.app/blog/consistency-guarantees): Deep dive into Lunar's distributed systems design: event sourcing, idempotency, and saga patterns used to maintain consistency across 100+ microservices in a regulated financial context. (2019)

- [Domain-Driven Design at Lunar](https://engineering.lunar.app/blog/domain-driven-design): How Lunar applies DDD principles (bounded contexts, ubiquitous language, aggregate design) to organize 250+ microservices across autonomous squads. References Evans and Fowler. (2022)

- [Introducing shuttle](https://engineering.lunar.app/blog/introducing-shuttle): Lunar's open-source tool for centralizing shared scripts and configuration across 70+ microservices in a polyrepo setup. Written in Go. (2019)

- [Adopting Go at Lunar Way](https://engineering.lunar.app/blog/adopting-go-at-lunar-way): How Lunar migrated its backend from Node.js and Ruby to Go. Covers runtime, concurrency model, and team learning curve. (2017)

- [From Rails Monolith to Microservices](https://engineering.lunar.app/blog/from-rails-monolith-to-microservices): First-hand account of decomposing a Ruby on Rails monolith into microservices at a fintech startup. Covers architecture decisions, pitfalls, and team structure. (2018)

## Conference Talks

Lunar engineers speak regularly at KubeCon North America, KCD Denmark, DDDEurope, and BigDataLDN. Talk recordings are listed at https://engineering.lunar.app/talks

## Open Source

Lunar maintains open-source tooling at https://github.com/lunarway including shuttle (script centralization for polyrepo microservices) and release-manager (Kubernetes release automation).