Michal Budzyn - Senior Golang Engineer

Königswinter, Germany

Experience

Dec 2024 - Present

1 year 2 months

Senior Golang Engineer

STACKIT / Schwarz Gruppe

Responsible for software engineering and DevOps in the Data & AI Platform - Intake and PubSub projects at STACKIT, the cloud provider of the Schwarz Group.
Technologies: Golang, Kubernetes, Kubernetes operators, OpenAPI v3, REST API, Azure DevOps, CI/CD, k6, Kafka, Strimzi, Apache Iceberg, RBAC, IAM, Terraform, Helm, Infrastructure automation, Load balancing, Traefik, ArgoCD, kuttl, Kyverno chainsaw, Kustomize, Velero, Prometheus, Grafana, Checkly / Playwright (TypeScript), NATS/Jetstream, WebSockets, gRPC, SSE

May 2024 - Nov 2024

7 months

Senior Golang Engineer

IONOS / United Internet

Decoupled managed Kubernetes from the IONOS Cloud API and developed new APIs for Kubernetes cluster and node pool management following IONOS Cloud API guidelines.
Implemented features for cluster management, node pool management and node management.
Integrated with IAM for enhanced security and maintained comprehensive documentation.
Ensured optimized API response times.
Technologies: Golang, Java, Kubernetes, CI/CD, GitHub Enterprise, GitHub Actions, Swagger / OpenAPI v3, REST API, Postgres, pgx, gRPC, event-driven and hexagonal architecture concepts, NATS / JetStream, contributions to kubernetes-sigs/controller-tools, Testcontainers

Jan 2022 - Mar 2024

2 years 3 months

Senior Backend Developer

German Edge Cloud

Implemented core components of the operation center: multi-cloud management and orchestration tools and code generators.
Developed a VPNaaS solution using Kubernetes operators.
Evaluated LXD for the edge and created a POC for cloud-native edge based on metal3.
Developed modules for platform provisioning of bare-metal and hybrid-cloud components based on the actor model.
Designed technical solutions and built a central edge proxy using REST over WebSocket for restricted environments and reverse HTTP proxy over QUIC.
Technologies: Kotlin, Golang, Java, Spring Boot, OpenStack, AWS, Terraform, GitLab CI/CD, Kubernetes (k3s, k3d), Docker, Helm, Kubebuilder, Postgres, BoltDB, REST, JWT, WebSockets, QUIC, gRPC, gin-gonic, microservices, GORM, Temporal.io, Prometheus, Terraform Plugin Framework, Earthly, Packer, OpenVPN, RSA, TLS, CRL, Carvel tools, Node.js/TypeScript, Jest, GCP K8s Config Connector, Azure Service Operator, Canonical Juju, Metal3, Kubernetes ClusterAPI / CAPI, mTLS, L4/L7 load balancing

Oct 2021 - Nov 2021

2 months

Senior Golang Developer

Applike Group / Adjoe

Refactored and improved performance of Adjoe backend services under high traffic conditions.
Technologies: Golang, AWS (SQS, SNS, ECS), GitLab, Terraform, Docker Compose, gin-gonic, Ginkgo, GoMock, pprof, Postman, RESTful microservices

Apr 2021 - Sep 2021

6 months

Senior Golang Developer

Kubermatic / SAP

Developed the Kyma project, a Kubernetes service platform.
Technologies: Golang, Kubernetes, Istio, Helm, CRD controllers, X.509, mTLS, GCP, Azure

Nov 2020 - Apr 2021

6 months

Kotlin / Java Developer

Metronom GmbH

Developed microservices for the METRO Companion App.
Technologies: Kotlin, Java, Spring Boot, GCP, Kubernetes, BigQuery, Swagger / OpenAPI, OAuth2, OpenID Connect, JWT, Jenkins, Gradle, GitLab, GitHub, Datadog, Postgres, RabbitMQ, WebFlux

Jul 2020 - Sep 2020

3 months

Senior Java Backend Developer

Lufthansa AirPlus Servicekarten

Developed microservices for secure communication between a mobile app and the virtual credit card management system.
Technologies: Java, Spring Boot, Spring Cloud, Microsoft Azure, AKS, Docker, Helm, Jenkins, SQL Server, Apache Kafka, PCI compliance, OAuth2, OpenID Connect, Keycloak, JOSE, JWT, JWE, RSA, JPA, Hibernate, Swagger / OpenAPI, Kotlin

May 2019 - Dec 2019

8 months

Golang Developer

Live Reply

Developed A4 POD Access Orchestrator, an SDN controller, and a RADIUS proxy for FTTH/FTTB subscribers of Deutsche Telekom.
Technologies: Golang, bare-metal Kubernetes, Docker, Kafka (confluent-kafka-go, Sarama), NATS Streaming, gRPC, etcd3, REST, RADIUS, UDP, network programming, Prometheus, Grafana, gin-gonic, GitLab, Helm, CI/CD

Jul 2018 - Jun 2020

2 years

Backend Architect and Developer / DevOps Engineer

Xarvio-BASF

Designed and developed a new service platform on Kubernetes and migrated existing Java services.
Developed application security features, proof of concepts, service monitoring, and alerting.
Built an image processing pipeline using TensorFlow GPU, AWS Batch, Step Functions, and Lambda.
Technologies: Java, Spring Boot, Spring Cloud, Golang, Python, WebSockets, AWS, Kubernetes, Docker, Helm, Linkerd2, EKS, Postgres RDS, RabbitMQ, Terraform, kubebuilder, Packer, Elasticsearch, Kibana, Calico, Fluentd, Prometheus, Grafana, OpenTracing Zipkin/Jaeger, OAuth2, OIDC, autoscaling (custom metrics, Karpenter, KEDA), Argo CD, Flux

Jan 2017 - Jun 2018

1 year 6 months

Platform Developer

REWE Digital

Developed core platform services: push, SMS, and email communication services.
Built a secret management solution for microservices in Kubernetes using Vault sidecars, custom plugins, and Spring Vault extensions.
Created Prometheus exporters for service monitoring and a Kafka proxy prototype in Golang.
Supported migration of an on-premise e-commerce platform to GCP.
Technologies: Golang, Java 8, Spring Boot, RxJava, Kubernetes, GCP, Docker, Docker Swarm, Consul, Prometheus, Kafka, OAuth2, HashiCorp Vault, Terraform, FCM, Nexmo SMS

Sep 2016 - Dec 2016

4 months

Senior Java Backend Developer

REWE Digital

Developed a basket service for REWE online shop delivery.
Migrated and enhanced software to support a new marketplace architecture.
Technologies: Java 8, Microservices, Docker, Spring Boot, Play 2, Kafka, Event Sourcing, PostgreSQL, Redis, Liquibase, JUnit

Sep 2015 - Aug 2016

1 year

Senior Java Backend Developer

Zalando SE / Zalando Payments SE

Developed risk management backend services for order screening and fraud detection.
Designed and prototyped an API gateway, distributed stream processing, and data lake repository.
Built a high-level event bus interface over Kafka-like queues with failover, load distribution, offset management, and leader election.
Technologies: Java 8, AWS, Docker, Spring Boot, Spring Cloud, RxJava, Kafka, SolrCloud, PostgreSQL, DynamoDB, Elasticsearch, Cassandra

Sep 2013 - Sep 2015

2 years 1 month

Senior Java Backend Developer / Technical Architect

HRS Group

Developed infrastructure and framework components for a multi-datacenter hotel self-administration system.
Built inventory, reservation, booking engines, distributed off-heap caches, multicast-based service discovery, and audit solutions.
Conducted performance testing, micro-benchmarking, profiling, and GC tuning.
Technologies: Java, Apache Cassandra, Redis Sentinel, Zipkin, Spring, Hibernate, JBoss, Linux, REST, JMS, RabbitMQ, AWS, Protocol Buffers

Jun 2013 - Aug 2013

3 months

Senior Software Developer Java EE

OTTO Group

Developed a high-performance Java EE e-commerce backend platform.
Technologies: Java EE, Glassfish, Spring, Oracle DB, Hibernate, JPA, Jenkins, JAX-B, SOAP, REST

Jan 2012 - May 2013

1 year 5 months

Senior Software Developer

Deutsche Telekom AG

Enhanced an online charging server to comply with EU roaming spending caps, handling up to 3000 req/s per node with 99.999% availability.
Implemented rating modules, ARP logic, SOAP services, Diameter-Gy IPv6 support, Wireshark dissectors, and Python simulators.
Technologies: Java, Python, SOAP, Diameter, LDAP, Jenkins, Oracle 10g

Jul 2011 - Dec 2011

6 months

Senior Software Developer

Deutsche Telekom AG

Enhanced INOX OCS SSD functionality and implemented a new SOAP interface to PCRF.
Optimized mass interactions for end-of-month scenarios and added 'Social Hours'.
Technologies: Java, SOAP, Diameter, SMS7, Jenkins, Oracle

Dec 2010 - Jun 2011

7 months

Senior Software Developer

Deutsche Telekom AG

Implemented INOX OCS for international roaming data vouchers and integrated with Huawei GGSN.
Technologies: Java, Diameter, LDAP

Mar 2010 - Nov 2010

9 months

Senior Software Developer

Deutsche Telekom AG

Evaluated and tested NSN IN Advantage 8.1 and SCE, refactored T-Mobile Primo Services, and implemented cNTDB LDAP interface.
Technologies: Java, SS7, SOAP, Diameter

Jun 2009 - Mar 2010

10 months

IN Application Developer

Deutsche Telekom AG

Designed and implemented MOC, MTC, web-initiated calls, USSD services, CAMEL coding, and integrated MultiSIM, MNP, HomeZone.
Technologies: Java, SS7, ASN.1

Feb 2009 - May 2009

4 months

IN Application Developer

T-Mobile International

Implemented legal interception, T-VPN call manager, and DTMF administration on NSN IN Advantage v7.5.
Technologies: Java, ASN.1, CORBA

Aug 2008 - Jan 2009

6 months

Senior System Developer

ATIS systems GmbH

Designed and implemented email and IP CTI for a telecom interception solution, including mass data processing, search engine provisioning, and recovery routines.
Technologies: Java 6, Oracle 11g, Hibernate, Spring, AOP

May 2008 - Jul 2008

3 months

Senior Software Developer

T-Mobile Germany

Implemented business logic and license management for a new generation voicemail system, integrated with ESB.
Technologies: Java 6, Hibernate, Spring

Jan 2008 - Apr 2008

4 months

Senior Software Developer

T-Mobile Germany

Refactored SPC and HCS interfaces with dynamic MBeans.
Technologies: Java 5, Hibernate, Spring

Jul 2007 - Dec 2007

6 months

Software Developer

T-Mobile Germany

Developed a CORBA-based module for MNP, HomeZone, and MultiSIM administration.
Technologies: Java 5, CORBA

Apr 2007 - Jun 2007

3 months

Software Developer

T-Mobile Germany

Developed a Java plugin for VPN administration using ONC/RPC and multithreading.
Technologies: Java 5

Dec 2006 - Mar 2007

4 months

Software Developer

T-Mobile Germany

Built a persistence layer generator for Java model classes and stored procedures, ported C++ logic to Java.
Technologies: C++, Java 5, Hibernate

Oct 2006 - Nov 2006

2 months

Software Developer

T-Mobile Germany

Ported C++ XOR-provisioning module to Java and developed test clients.
Technologies: Java 5

Jan 2006 - Sep 2006

9 months

Software Developer

T-Mobile Germany

Designed and implemented a SOA provisioning interface between customer care and core network administration with Tibco adapters.
Technologies: Java, C++

Sep 2005 - Dec 2005

4 months

Software Developer

T-Mobile Germany

Enhanced the Homezone provisioning system and developed stored procedures for USSD CAMEL triggers.
Technologies: C++, Oracle

Jul 2005 - Aug 2005

2 months

Software Developer

T-Mobile Germany

Enhanced CRM workflow and messaging for Combi-Card Teens products and developed Tibco adapters.
Technologies: C++, Java, Tibco

Apr 2005 - Jun 2005

3 months

Software Developer

T-Mobile Germany

Developed a bridge server between CRM and Ericsson MMSC proxy and a simulation application.
Technologies: Java, CORBA, SOAP

May 2004 - Sep 2004

5 months

Software Developer

T-Mobile Germany

Developed an identity server admin request processing application for CRM workflows.
Technologies: C++, Oracle

Feb 2004 - Mar 2005

1 year 2 months

Release Manager

T-Mobile Germany

Managed releases for Subscriber Mediation Device project, planned budgets, resources, schedules, and external contracts.

Dec 2003 - Jun 2004

7 months

Software Developer

T-Mobile Germany

Developed the International Service Provisioning Component system connecting CRM, subscription server, and portals.
Technologies: Java, Oracle

Jun 2003 - Sep 2003

4 months

Software Developer

T-Mobile Germany

Built a lock-server for prepaid SMS-MO warm billing with workflow and data migration.
Technologies: C++, Java

Apr 2002 - Oct 2002

7 months

Software Developer

T-Mobile Germany

Developed a batch application for MNP porting requests and a master routing DB simulator.
Technologies: C++, Java, Shell scripting

Jan 2002 - Jun 2003

1 year 6 months

Software Developer

T-Mobile Germany

Developed and supported an online prepaid load system, designed database migration, and SAP data transfer processes.
Technologies: Oracle, Shell scripting

Nov 2000 - Mar 2005

4 years 5 months

Software Developer / Project Carmen

T-Mobile Germany

Developed stored procedures, tuned a VLDB core network and resource administration database (300M+ records) with partitioning, materialized views, and replication.
Technologies: Oracle 7/8i, SQL, PL/SQL, C++, Shell scripting

Jul 1999 - Oct 2000

1 year 4 months