Michal Budzyn
Senior Golang Engineer
Experience
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Senior Software Developer
Deutsche Telekom AG
- Implemented INOX OCS for international roaming data vouchers and integrated with Huawei GGSN.
- Technologies: Java, Diameter, LDAP
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
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
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
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
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
Senior Software Developer
T-Mobile Germany
- Refactored SPC and HCS interfaces with dynamic MBeans.
- Technologies: Java 5, Hibernate, Spring
Software Developer
T-Mobile Germany
- Developed a CORBA-based module for MNP, HomeZone, and MultiSIM administration.
- Technologies: Java 5, CORBA
Software Developer
T-Mobile Germany
- Developed a Java plugin for VPN administration using ONC/RPC and multithreading.
- Technologies: Java 5
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
Software Developer
T-Mobile Germany
- Ported C++ XOR-provisioning module to Java and developed test clients.
- Technologies: Java 5
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++
Software Developer
T-Mobile Germany
- Enhanced the Homezone provisioning system and developed stored procedures for USSD CAMEL triggers.
- Technologies: C++, Oracle
Software Developer
T-Mobile Germany
- Enhanced CRM workflow and messaging for Combi-Card Teens products and developed Tibco adapters.
- Technologies: C++, Java, Tibco
Software Developer
T-Mobile Germany
- Developed a bridge server between CRM and Ericsson MMSC proxy and a simulation application.
- Technologies: Java, CORBA, SOAP
Software Developer
T-Mobile Germany
- Developed an identity server admin request processing application for CRM workflows.
- Technologies: C++, Oracle
Release Manager
T-Mobile Germany
- Managed releases for Subscriber Mediation Device project, planned budgets, resources, schedules, and external contracts.
Software Developer
T-Mobile Germany
- Developed the International Service Provisioning Component system connecting CRM, subscription server, and portals.
- Technologies: Java, Oracle
Software Developer
T-Mobile Germany
- Built a lock-server for prepaid SMS-MO warm billing with workflow and data migration.
- Technologies: C++, Java
Software Developer
T-Mobile Germany
- Developed a batch application for MNP porting requests and a master routing DB simulator.
- Technologies: C++, Java, Shell scripting
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
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
Software Developer
Industrial and Financial Systems Poland
- Enhanced the IFS Applications ERP (Finance, Distribution, Maintenance), adapted to Polish law, and tuned performance.
- Technologies: Oracle 8, Solaris
Industries Experience
See where this freelancer has spent most of their professional time. Longer bars indicate deeper hands-on experience, while shorter ones reflect targeted or project-based work.
Experienced in Telecommunication (13 years), Information Technology (6 years), Retail (3.5 years), Agriculture (2 years), Tourism (2 years), and Fashion (1 year).
Business Areas Experience
The graph below provides a cumulative view of the freelancer's experience across multiple business areas, calculated from completed and active engagements. It highlights the areas where the freelancer has most frequently contributed to planning, execution, and delivery of business outcomes.
Experienced in Information Technology (26 years), Product Development (14 years), and Project Management (1 year).
Skills
Linux
Windows
Solaris
Java
C++
C
Sql
Pl/sql
Shell-script
Python
Lua
Golang
Kotlin
Oracle 7
Oracle 8
Oracle 8i
Oracle 9i
Oracle 10g
Mongodb
Redis
Cassandra
Postgresql
Tcp/ip
Udp
Dns
Dhcp
Ssh
Ftp
Snmp
Smtp
Ldap
Diameter
Ss7
Corba (Jacorb)
Soap (Axis, Cxf)
Hibernate
Tibco Sdk
Spring
J2ee
Osgi
Aop
Java Servlets
Tomcat
Nsn In Advantage 8.1
Jboss 7
Rabbitmq
Zookeeper / Exhibitor
Kafka
Amazon Web Services
Azure
Google Cloud Platform
Clearcase
Ddts – Tracking System
Toad
Eclipse
Powerdesigner
Totalview
Rational Purify
Precise Oracle
Ant
Junit
Hp Quality Center
Git
Svn
Intellij Idea
Maven
Gradle
Jenkins
Stash
Telecommunication
Distribution/sales
Accounting/finance
Energy Industry
E-commerce
Languages
Education
Kielce University of Technology
Bachelor in Management and Marketing · Management and Marketing · Kielce, Poland
Kielce University of Technology
Master's degree in Computer Science · Computer Science · Kielce, Poland
Certifications & licenses
AWS Certified Developer Associate Level
Amazon Web Services
Oracle Certified Professionalist In 8i/9i
Oracle
Profile
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