Work Experience

• Senior Backend Engineer, Personio SE & Co. KG Munich

  Jun, 2018 - Present

  • Plan and implement a whistleblowing service featuring anonymous employee case reporting and a case management user interface (Golang, GRPC, Postgresql, AWS CDK)

  • Develop and ship a golang kafka event consumer as part of the whistleblowing and conversations projects

  • Enable rich text editing for an employee help-desk system by parsing input sources (E-Mail, Web, Slack) into a common format for storage and output formatting (Golang, Protobuf, Postgresql)

  • Migrate access rights of hundreds of customers to a microservice (PHP, SQS, Kotlin) and validate through feature flags and parallel run

  • Design and implement a Project to asynchronously scan files for viruses using golang, ClamAV and AWS SQS

  • Migrate >6 mio files to AWS S3 encryption at rest

  • Identify performance bottlenecks in the existing monolith (PHP) - implement and deploy vast improvements to most used endpoints

  • Drive multiple Laravel Framework upgrades

  • Identify and fix file upload related issues

• Senior Backend Engineer, OC Development GmbH Prien am Chiemsee

  Dec, 2017 - May, 20186 months

  • Manage and improve the existing codebase

  • Enable migration to MS Azure: Translate the existing infrastructure into a terraform project, provision it and deploy the codebase as a prototype

  • Design and implement a service to asynchronously configure voip phone and remote desktop setups

  • Coach colleagues in technical topics and agile methods

• Senior Backend Engineer, PosterXXL GmbH Munich

  Jun, 2017 - Nov, 20176 months

  • Maintain and improve the web shop and background services (Symfony 2, AWS)

  • Identify and fix random logouts by refactoring the session and shopping cart handing (AWS DynamoDB)

  • Plan and develop an internal batch import tool to support other departments

  • Create a concept and implement a service for handling background workers: Infrastructure (AWS Cloudformation), Continuous integration and deployment (Gitlab pipelines), Linting and testing, Monitoring and alerting (AWS Cloudwatch, Logstash, Kibana), Project setup (Symfony 3, Docker)

• Full-Stack Software Engineer, joblocal GmbH Rosenheim

  Jun, 2015 - May, 20172 years

  • Increase performance of the high traffic pages by analysing and refactoring database n+1 queries, business logic (NewRelic), optimizing data- and asset caching (Memcached, AWS Cloudfront)

  • Improve monitoring and alerting: Provide TV Status Board and an error monitoring tool with integrated ticket creation (AWS Cloudwatch, Geckoboard, Airbrake, Jira)

  • Reduce cost by introducing automatic ssl certificate management for 30+ domains (certbot, AWS Certificate Manager, AWS Route53)

  • Design, implement, test and document a comprehensive REST API (JSON-API Schema, Authentication, Rate Limiting, Caching - AWS Api Gateway)

  • Plan and provision infrastructure to host microservices: Infrastructure as Code (AWS Cloudformation)

  • Develop and apply security concept: Network (VPC, Firewall, Bastion) and Services (IAM Roles, Credentials)

  • Add load/message based automatic scaling (AWS ECS, Docker) and monitoring (AWS Cloudwatch)

  • Setup continuous integration and deployment using Jenkins Pipelines, PHPUnit

  • Create a concept about handling background processes like queued jobs and cronjobs as well as event pub/sub (AWS SNS and SQS)

  • Design and implement the local development environment (docker compose), test and production environments (AWS ECS)

  • Configure cost management (AWS Cost Allocation Tags/ Reports)

  • Plan, implement and deploy a microservice using test driven development (PHP Lumen) and migrate the data

  • Manage and provide support for Google Tagmanager

• Web Developer, WebTec Braun GmbH Rosenheim

  Jan, 2015 - May, 20155 months

  • Develop and support corporate websites and shops

  • Design and implement features for the experience gift voucher shop project

  • Manage linux server infrastructure

  • Identify and fix linux server performance issues: previous hosting provider change led to partition misalignmment

  • Technologies: LAMP Stack, Wordpress, OXID, Yii

• Full-Stack Software Engineer, joblocal GmbH Rosenheim

  Sep, 2011 - Dec, 20143 years 4 months

  • Identify, reproduce and fix bugs of the current job platform

  • Design and implement the next major version featuring multi-domain handling: Project architecture, database structure

  • Implement several domains (company, job_posting, job_application, ...) covering backend, frontend and workers in a team

  • Provision and manage linux server infrastructure: multiple webservers & loadbalancer, static content hosting & caching

  • Setup and manage the local development environment: automated linting and testing, build and deployment pipeline

  • Add infrastructure- and job platform monitoring and alerting/escalation (Zabbix, SMS)

  • Handle security related topics: iptables configuration, package/dependency updates and access control

  • Lead a major platform refactoring to provide multi-tenancy capability

  • Implement Apache Solr search integration (frontend, backend), install and configure the solr service, participate in search index optimization (synonym lists, scoring)

  • Design and implement a scalable system to run scheduled search queries based on customer saved search criteria

  • Develop a job vacancy email notification system triggered by scheduled search results (Mailchimp/Mandrill)

  • Cover business critical routes with automated end-to-end tests (PHPUnit, Selenium)

  • Evaluate and migrate to Amazon Web Services: provision infrastructure as code (AWS CloudFormation), replace self-hosted with AWS provided solutions (VPC, CloudWatch, EC2, RDS, S3, Elastic Beanstalk)

  • Office IT support, on-call duty

• Web Developer, eraffe media GmbH & Co. KG Rosenheim

  Mar, 2008 - Aug, 20113 years 6 months

  • Investigate and remove performance bottlenecks of the eraffe.de community portal

  • Reproduce and fix most important bugs

  • Design and implement the next version 3 of the eraffe.de community portal: design the database layout, develop the PHP/MySQL based backend as well as the HTML/JS frontend

  • Provision and manage linux server infrastructure

  • Technologies: PHP, HTML, JavaScript, MySQL, Apache, Nginx, Varnish Memcached/ APC SphinxSearch

• Web Developer, Kuse GmbH Werbeagentur Traunstein

  Sep, 2004 - Feb, 20083 years 6 months

  • Develop and maintain a PHP/MySQL based content management system

  • Design and implement corporate websites using the CMS

  • Provision and manage a hosted linux server

  • Design and prototype a single page app to evaluate a new ad format

  • Technologies: PHP, HTML, JavaScript, MySQL, Apache, Debian

• Application Development Trainee, NEW LOOK electronic publishing GmbH Munich

  Sep, 2001 - Aug, 20043 years

  • Refine, merge and import ADAC and other car databases from MS Access/ CSV to Sybase

  • Enable online total cost of ownership calculation for cars (https://adac-autokosten.de) by refactoring the ADAC Autokosten Backend written in Visual Basic to Java

  • Support the relaunch of https://auto-news.de: Develop a web crawler in Perl to migrate MS Frontpage pages to structured XML

  • Create and test ADAC Autokosten and Auto-News CD-ROM releases

  • Implement features for Auto-News and ADAC Autokosten using JSP and PHP

  • Take first steps with linux server administration

Skills