Michael König

Architect and Full-Stack Developer

Avatar placeholder
Dresden, Germany

Experience

Nov 2024 - Feb 2024
-1 years -8 months
Lorem ipsum dolor sit amet

Atruvia AG

  • Further development of framework components and services for the Enterprise Bank Control Platform (EGP framework), a collection of cross-cutting libraries and services for all bounded context scopes of the platform.
  • Carried out migration from Java 17 to Java 21 and Spring Boot 3.2 to 3.4 across about 80 library and service repositories (updating Maven POMs, Dockerfiles, Jenkins pipelines, source code migration, test evolution).
  • Developed unit and integration tests with JUnit and JGiven.
  • Conducted and analyzed performance measurements with Dynatrace.
  • Enhanced multi-stage CI/CD pipelines (unit tests, security analyses, Docker build, Harbor deployment, ...).
  • Tech stack used: Java (90%), Python (10%), Spring Boot, JPA/Hibernate, JGiven, OpenAPI, Camunda 7, Podman, OpenShift/Kubernetes, Oracle DB, SonarQube, Dynatrace, Jenkins, Harbor, Bitbucket, Jira, Confluence.
May 2024 - Present
1 year 8 months

Architect and Full-Stack Developer

Klareau GmbH

  • Worked in a very small team (three people) to develop a modern platform for calculating and simulating complex processes in wastewater treatment plants (planning and operation).
  • Ensured a robust and scalable software architecture and adherence to modern development methods (Scrum, CI/CD, cloud-native, DDD, TDD, shift-left).
  • Supported both online and offline use of the application (office PC, iPad without internet connection on site at the treatment basin).
  • Gathered and documented requirements and quality objectives (functional and non-functional).
  • Designed and documented a flexible and high-performance software architecture (Arc42, UML, BPMN).
  • Built robust "self-healing" and cost-efficient "auto-scaling" cloud infrastructures as infrastructure as code with Terraform and GitLab CI.
  • Implemented monitoring and alerting mechanisms in the cloud.
  • DevOps development of CI/CD pipelines with GitLab, including various test stages (shift-left approach), static code quality and security scans (on code and container level).
  • Defined REST APIs in a contract-first approach with OpenAPI.
  • Developed microservices with Kotlin and Java based on Spring Boot and MongoDB.
  • Contributed to the Angular frontend to a limited extent.
  • Tech stack used: AWS Elastic Kubernetes Service (EKS) with AWS Fargate, MongoDB, CloudFront, CloudWatch, Elasticsearch, Kibana, Kotlin, Spring Boot, Angular/TypeScript, Helm, Terraform, GitLab CI/CD.
Jun 2023 - Apr 2024
11 months

Architect and Full-Stack Developer

Atruvia AG

  • Played a key role in developing and implementing a cloud service that enables Atruvia customers to host their own services within a cloud infrastructure.
  • Designed and built a marketplace as a central shop system for ordering and configuring cloud services.
  • Developed microservices in Java, Kotlin, TypeScript, and Python, mainly with Spring Boot (approx. 70%) and Angular (approx. 30%).
  • Implemented REST controllers, services, entities, and repositories following domain-driven design principles.
  • Performed performance tuning using efficient caching with Redis and using MongoDB and Postgres.
  • Integrated with a single sign-on system using OAuth2 and OpenID.
  • Adapted and extended existing and implemented new Angular components and services focusing on TypeScript and HTML.
  • Optimized and documented the system architecture and modeled interfaces to the in-house frontend and to internal and external microservices.
  • Switched from code-first to contract-first with OpenAPI and introduced generated client and server stubs for backend and frontend.
  • Wrote unit and integration tests for the Java and Kotlin backend with JUnit and EasyMock.
  • Implemented and integrated load and performance tests with JMeter into the CI pipeline.
  • Wrote frontend tests with Jasmine and end-to-end tests with Cypress, including mandatory execution on every merge request in the CI/CD pipeline.
  • Enhanced multi-stage CI/CD pipelines (security analyses, E2E tests with Cypress, load tests with JMeter, Docker build, Harbor deployment, ...).
  • Technologies and tools used: Java, Kotlin, TypeScript, Python, Spring Boot, JPA/Hibernate, Angular, OpenAPI, Docker, OpenShift/Kubernetes, Helm, GitLab, Redis, Postgres, MongoDB, Grafana, Cypress, JMeter, DDD, TDD, Scrum, SAFe.
Sep 2020 - May 2023
2 years 9 months

Interim-CTO, Solution Architect and Developer

FI Freiberg Institut GmbH

  • Took on the role of interim CTO and software architect for a simulation and multi-objective optimization software (Edgar) for planning and optimizing energy systems.
  • Analyzed and reviewed the existing monolithic prototype, which was hosted directly on developers' PCs (code and architecture review, due diligence).
  • Designed a target system architecture as a cloud-native application and broke the monolith into multiple microservices with major functional enhancements.
  • Defined interfaces in a contract-first approach using OpenAPI and automated code generation.
  • Selected a suitable cloud provider and built the infrastructure in AWS with Terraform.
  • Implemented cloud security following the principle of least privilege.
  • Set up and maintained CI/CD pipelines with GitLab, deploying to AWS as Docker containers (initially Elastic Beanstalk, later Kubernetes).
  • Designed a software architecture to meet user volume and performance requirements, including autoscaling, monitoring, and alerting.
  • Defined the test pyramid (unit, integration, end-to-end, and performance tests).
  • Implemented new features, especially in user management and billing.
  • Introduced an event-driven architecture with Kafka.
  • Implemented logging and monitoring with ELK stack/Kibana, Grafana, AWS X-Ray, and CloudWatch.
  • Established an agile software development process, including selecting and setting up the toolchain.
  • Led the team, managed risks, and worked closely with management and the development/DevOps team.
  • Ensured reliability, performance, and high availability of the application during deployments and load peaks while keeping costs efficient; confirmed by AWS for consistent implementation of the Well-Architected Framework.
  • Technical base: backend services mainly on Spring Boot/Kotlin, simulation and multi-objective optimization core as a genetic algorithm using jMetal, frontend with Vue.js/TypeScript.
  • Tools and technologies used: Spring Boot, GitLab, Amazon AWS (ECS, EC2, Elastic Beanstalk, Lambda, Route 53, ALB, S3, CloudFront, SQS/SNS, CloudWatch, RDS, VPN, MSK), Kafka, Vue.js, Grafana, jMetal, Postgres, ClickUp.
  • Relevant skills: cloud-native architecture, microservices, Kotlin, Java, JPA, REST, messaging, OAuth2/OpenID, UML, domain-driven design, test-driven design/shift-left, Scrum, OKR.
Oct 2017 - May 2020
2 years 8 months
Hanover, Germany
Lorem ipsum dolor sit amet

TUI Infotec GmbH

  • Developed a highly available, self-healing microservice system for booking flight extras (e.g., seats, extra baggage, meals) to replace a third-party component.
  • Integrated numerous external and heterogeneous interfaces (airline carrier systems and TUI internal systems).
  • Ran the microservices as Docker containers in a cluster within the Amazon AWS cloud infrastructure.
  • Coordinated interfaces with external partners and other teams.
  • Designed and documented the microservice system architecture.
  • Advised on and reviewed the development and deployment process (continuous integration, continuous delivery).
  • Created and monitored architecture guidelines and conducted code reviews.
  • Implemented central libraries and microservices.
  • Ensured quality with a focus on coding standards, test coverage, and documentation.
Jun 2015 - Sep 2017
2 years 4 months
Stuttgart, Germany
Lorem ipsum dolor sit amet

T-Systems International GmbH

  • Worked on the "Daimler Connected Car" project with the goal of migrating a complex monolithic JEE application on the WSO2 stack (Application Server, ESB, Identity Server, Governance Registry) into several standalone Spring Boot applications.
  • Designed and implemented a complex microservice architecture and subsequently added functional enhancements to the services.
  • Coordinated, specified, and documented each microservice (REST API, MQTT, JMS).
  • Implemented central libraries and microservices.
  • Created and monitored architectural guidelines and conducted code reviews.
  • Collaborated closely with other teams, central architecture, and client representatives.
  • Ensured quality in terms of coding conventions, test coverage, and documentation.
Oct 2014 - Apr 2015
7 months
Dresden, Germany
Lorem ipsum dolor sit amet

T-Systems Multimedia Solutions GmbH

  • Worked on the telemedicine project "Carus Consilium Sachsen".
  • Performed performance and memory analyses and tuned the application.
  • Identified and resolved scaling and threading issues.
  • Conducted code and architecture reviews.
  • Implemented various base classes and framework code.
  • Architected and managed cross-cutting concerns such as authentication/authorization, performance, caching, logging, transactions, and exception handling.
Jul 2013 - Aug 2013
2 months
Nuremberg, Germany
Lorem ipsum dolor sit amet

ING-DiBa

  • Performed code and architecture reviews of various internally used banking applications.
  • Advised on security and performance aspects of existing software components.
Sep 2010 - Sep 2014
4 years 1 month
Dresden, Germany
Lorem ipsum dolor sit amet

T-Systems Multimedia Solutions GmbH

  • Worked on the large-scale "De-Mail" project (over 100 team members, project language English).
  • Analyzed functional and technical requirements and estimated effort.
  • Modeled business processes using BPMN and UML, and use cases (in UML and textual form).
  • Derived the target architecture and required system components.
  • Defined entities and the data model.
  • Aligned interfaces and system boundaries.
  • Defined the use of frameworks, APIs, and central tools.
  • Created the IT concept.
  • Planned work packages and led architects and developers.
  • Reviewed architectural and development results (code and architecture reviews).
  • Coached developers.
Nov 2008 - Aug 2010
1 year 10 months
Berlin, Germany
Lorem ipsum dolor sit amet

Lufthansa Systems Berlin GmbH

  • Architected and developed a proprietary ORM framework, architecturally inspired by JPA, JDO, Hibernate, and Rails ActiveRecord.
  • Implemented various services in the business layer and domain model layer within a service-oriented architecture (SOA).
  • Performed performance and stability analyses.
  • Detected and fixed scaling and multithreading issues.
Aug 2008 - Oct 2008
3 months
Darmstadt, Germany
Lorem ipsum dolor sit amet

General Electric Energy GmbH

  • Java development in the field of geo-data visualization (GIS), order and cooperation management.
  • Conducting performance, stability and code quality analyses.
  • Creation of JUnit and Cactus tests.
  • Configuration, streamlining and tuning of a JBoss cluster (cluster architecture).
Lorem ipsum dolor sit amet

ITEC GmbH

  • Development of the heat pump sizing program "WDim" for sizing heat pump systems for single-family and multi-family homes.
  • Implementation of various modules for cost-effectiveness analysis with comparison options for alternative heat generators and sources, as well as calculation of heat demand using different methods.
  • Creation of the software architecture.
  • Implementation of the desktop application.
  • Technical project management.
Lorem ipsum dolor sit amet

T-Systems Multimedia Solutions GmbH

  • Participation in the "Telekom HR-Portal" project to integrate various legacy applications and new software components into an SOA (OSGi component architecture; frontend as a rich internet application with a web desktop interface).
  • Creation of the IT concept.
  • Prototyping and development of a proof of concept.
  • Development of the software architecture.
  • Technical consulting and technical project management.
  • Reviews of architecture and development results.
  • Coaching of developers.
Lorem ipsum dolor sit amet

T-Systems Multimedia Solutions GmbH

  • Participation in the "Human Resources Management – Job Exchange of Deutsche Telekom AG" project (international and fully localized for deployment in, among others, Austria, Switzerland, South Africa, Spain).
  • Technical project management.
  • Analysis of client requirements and creation of business and IT concepts.
  • Workflow modeling (Business Process Management).
  • Creation of an application prototype.
  • Development of the software architecture.
  • Support for development and functional/technical consulting.
  • Development of a workflow engine and a highly complex rights/roles concept.
  • Quality assurance as well as coaching and support of project team members.

Summary

AWS Cloud Architect and developer (Java/Kotlin, Spring) with over 20 years of experience. As an analytical problem solver, I enjoy using creative solutions and continuously develop my skills to broaden and deepen my expertise. My main focus is on solution and software architecture, backend development, and DevOps. With many years of experience and curiosity, I balance effectiveness and high quality standards with a healthy dose of pragmatism and efficiency.

Skills

  • Architecture And Development In The Cloud Environment (Cloud-native Microservices And Soa)

  • Design, Analysis, Implementation, And Optimization Of Software Architectures Or Components

  • Reviews And Assessments, Due Diligence At Architecture And Source Code Level

  • Performance Tuning As Well As Analysis And Resolution Of Scaling Or Multithreading Issues

  • Consulting And Coaching

  • Java

  • Kotlin

  • Typescript

  • C/c++

  • C#

  • Delphi

  • Groovy

  • Javascript

  • Pascal

  • Php

  • Pl/sql

  • Python

  • Ruby

  • Xslt

  • Mariadb/mysql

  • Oracle

  • Postgresql

  • H2

  • Hsqldb

  • Ms Sql Server

  • Sqlite

  • Cassandra

  • Dynamodb

  • Mongodb

  • Neo4j

  • Objectdb

  • Linux

  • Mac Os

  • Sun Os

  • Solaris

  • Windows

  • Agile Methods (Scrum, Kanban, Safe, Okr)

  • Aspect-oriented Programming (Aop, Spring And Aspectj)

  • B2b, B2c

  • Big Data Analysis

  • Business Process Modeling (Bpmn)

  • Code Review, Refactoring, Reengineering

  • Database Design

  • Design Patterns / Antipatterns

  • Enterprise Application Integration (Eai)

  • Event-driven Architecture (Eda)

  • Genetic Algorithms

  • Internationalization / Localization (I18n/l10n)

  • Microservices (Especially With Spring Boot)

  • Model-driven Architecture (Mda)

  • Object-oriented Analysis / Programming / Design (Ooa / Oop / Ood)

  • Security, Single Sign-on (Sso)

  • Service-oriented Architecture (Soa)

  • Simulations (Mathematical / Physical)

  • Software Development And Architecture

  • Test-driven Development (Tdd)

  • Uml

  • Web Frameworks (Various)

  • Web Services (Soap, Rest, Rpc)

  • Cloud Architectures And Microservices

  • Java Se (Concurrency, Instrumentation, Jaxb, Jdbc, Jpa, Jmx, Reflection,…)

  • Java Ee (Ejb, Jaas, Jndi, Jsp, Jta, Jms, Ws*, Jax-rs, Interceptors, Cdi,…)

  • Jruby / Ruby On Rails

  • Kotlin

  • Netflix Oss (Feign, Ribbon, Hystrix, Eureka, Zuul,…)

  • Spring (Boot, Aop, Mvc, Data, Remoting, Security, Webservices, Integration, Batch,…)

  • Activemq

  • Arquillian

  • Eclipselink

  • Hibernate

  • Jmetal Framework (Multi-objective Optimization/metaheuristic)

  • Jmeter

  • Junit, Testng, Mockito, Easymock, Powermock

  • Maven

  • Openshift/kubernetes

  • Docker

  • Selenium

  • Spring Framework

  • Glassfish

  • Jboss

  • Jetty

  • Resin

  • Tomcat

  • Undertow

  • Weblogic

  • Wildfly

  • Wso2 Application Server (Incl. Esb, Is, Governance Registry)

  • Artifactory

  • Atlassian Jira, Confluence, Bamboo, Fisheye, Crucible

  • Cast

  • Eclipse / Spring Tool Suite

  • Fortify (Hp)

  • Gitlab, Github

  • Intellij Idea

  • Jenkins/hudson

  • Ibm Rational Suite (Synergy, Rose, Clearcase, Clearquest)

  • Redmine

  • Soapui

  • Sonarqube

  • Sparxsystems Enterprise Architect

Languages

German
Native
English
Advanced

Certifications & licenses

AWS Certified Developer – Associate (DVA)

AWS Certified Solutions Architect – Associate (SAA)

ISaqB Certified Professional For Software Architecture, Advanced (CPSA-A)

SpringSource Certified Enterprise Integration Specialist (SCEIS)

OMG Certified Expert In Business Process Management - Fundamental (OCEB-F)

OMG Certified UML Professional – Intermediate (OCUP-I)

Need a freelancer? Find your match in seconds.
Try FRATCH GPT
More actions

Similar Freelancers

Discover other experts with similar qualifications and experience

Hüseyin Korkut
Hüseyin Korkut

Senior Full-Stack Engineer

View Profile
Lothar Hinsche
Lothar Hinsche

Solution Manager for PoC investigation and replacement and refinement of an existing cloud and IoT power plant control system

View Profile
Thomas Jarnot
Thomas Jarnot

Backend Developer, DevOps Engineer

View Profile
Thomas Hoefkens
Thomas Hoefkens

Senior MLOps, DevOps Engineer

View Profile
Werner Keil
Werner Keil

Test Coordinator, Designer and Engineer

View Profile
Jürgen Fey
Jürgen Fey

AR/VR/XR Architect

View Profile
Ulrich Cech
Ulrich Cech

Java Architect/Developer – Freelancer

View Profile
Alexander Kapincev
Alexander Kapincev

Senior Fullstack Developer

View Profile
Jens Rehsack
Jens Rehsack

Technical Product Owner

View Profile
Jan Mönnich
Jan Mönnich

Interface project at HR Solutions GmbH for Rhineland-Palatinate / BAMF

View Profile
Matthias Kittner
Matthias Kittner

General ERP and AI Consulting

View Profile
Achille Chimi
Achille Chimi

Backend/Frontend Developer

View Profile
Jan Lüders
Jan Lüders

Senior Developer

View Profile
Joseph Wagner
Joseph Wagner

Cloud Solution Architect / Solution Architect

View Profile
Dirk Bolte
Dirk Bolte

Senior Software Developer

View Profile
Patrick Eichler
Patrick Eichler

Kubernetes Expert | Google Cloud Platform Engineer

View Profile
Anton Klonov
Anton Klonov

Head of Technical Overall Integration NSC / Hadoop Cloud Development

View Profile
Sebastian Kanzow
Sebastian Kanzow

Senior Lead Developer, System Architecture

View Profile
Johannes Erchen
Johannes Erchen

Senior Application Developer

View Profile
Andreas Steffan
Andreas Steffan

Lead Developer

View Profile
Rainer Bieniek
Rainer Bieniek

Senior Developer

View Profile
Manuel Reinfurt
Manuel Reinfurt

Cloud Architect & Lead Developer

View Profile
Florian Fladung
Florian Fladung

Senior Backend Developer

View Profile
Andreas Kraus
Andreas Kraus

Senior Developer

View Profile
Thomas Stägemann
Thomas Stägemann

Rating System

View Profile
Ales Loncar
Ales Loncar

Senior DevOps Consultant (Freelance)

View Profile
Frank Eppink
Frank Eppink

DevOps

View Profile
Michal Budzyn
Michal Budzyn

Senior Golang Engineer

View Profile
Jan Mundo
Jan Mundo

Founder, Senior Solution Architect, TeamLead, Senior DevOps-Engineer

View Profile
Paul Webster
Paul Webster

Architecture Consultant (Freelance)

View Profile