Mario Ellebrecht
Freelance Developer
Experience
Jan 2022 - Present
2 years 7 months Ulm, Germany
Freelance Developer
Software Vendor
- Java 17 backend development with Spring Boot as lead developer
- Redesigned a custom production control system
- Created a customizable standard product based on a new proposed tech stack (Angular, GraphQL, Neo4j)
- BPMN support with bpmn.io and Flowable
- Realigned the agile development process
- Led open space workshops on technology topics
- Java 17, Spring Boot, GraphQL, Netflix DGS, Neo4j, Spring Data Neo4j, Liquibase Neo4j, Prometheus, Grafana, Docker, Kubernetes, Scrum/Kanban, Azure DevOps
Jan 2021 - Dec 2022
1 year Mannheim, Germany
Freelance Developer
Roche Diagnostics
- Java 11/Kotlin full-stack development with ZK OSS and Spring Boot
- Data ingest and persistence with Kafka, ActiveMQ, MongoDB
- Domain model with domain-driven design (DDD)
- Event-driven architecture, event sourcing, CQRS
- Roadmap for GraphQL migration
- Kotlin, Ktor, Java 11, Spring, REST, ActiveMQ, Redis, MongoDB, Kafka, AWS, Docker, Kubernetes, Bitbucket, Selenium, Scrum, LS
Jan 2020 - Dec 2022
2 years Cologne, Germany
Freelance Developer
talentsconnect AG
- Kotlin backend development of GraphQL/REST microservices
- Persistence and graph processing with Neo4j/ONgDB
- Integrated various SSO services via OAuth2/SAML
- Kotlin, Ktor, Spek, Neo4j/ONgDB, GraphQL, Docker Swarm, AWS, Weblate, ELK, Prometheus, Grafana, Sentry, Locust, Scrum, arc42
Jan 2019 - Dec 2020
2 years Berlin, Germany
Freelance Developer
Deutsche Bahn Station&Service
- Java 11 backend development of various REST microservices
- Central platform for controlling distributed embedded devices
- Event-driven architecture with AMQP and Apache Kafka
- Java 11, Spring Boot, REST/HATEOAS, OpenAPI, RabbitMQ, Avro, Protocol Buffers, Kafka, Flyway, PostgreSQL, MongoDB, Redis, AWS, Acapela TTS, Kubernetes, Helm, GitLab, Selenium, Scrum/SAFe
Jan 2016 - Dec 2020
3 years Hanover, Germany
Freelance Developer
Volkswagen Commercial Vehicles
- Java 11 backend development with Spring Boot, Microsoft Azure
- Built a new GraphQL API as an aggregator for many REST microservices for VW ConnectFleet fleet management
- Later migrated to Spring WebFlux and reactive streams
- Domain model and GraphQL schema design
- Managed technical collaboration with VW, Audi, Porsche/MHP
- Java 11, Spring Boot, GraphQL Java, GraphQL SPQR, Kafka, Graal, Docker, Kubernetes, Helm, Azure, AWS, JIRA, Confluence, GitLab
Jan 2016 - Dec 2017
1 year Berlin, Germany
Freelance Developer
SearchInk/omni:us
- Java/Python backend development and software architecture
- Document search and classification with Apache Lucene
- Onboarding and support for machine learning tasks
- Natural language processing (Word2Vec, OCR, HTR)
- Python machine learning (Random Forest, SVM, k-means etc.)
- Deep learning (CNN, RNN) with TensorFlow, Keras and Torch
- Java SE 8, Python, Spring Boot, REST, Gensim, Google Cloud (GCP)
Jan 2015 - Dec 2017
2 years Berlin, Germany
Freelance Developer
Telefonica Next/Live Reply
- Java/Scala backend development and software architecture
- Built a new IoT platform in the B2B2C segment
- API client with dynamic Swagger/OpenAPI integration in Go
- IoT apps with BTLE, 2G and LPWAN (Sigfox, NB-IoT) connectivity
- Java SE 8, Go 1.8, Scala, Akka, Node.js, REST, CQRS, MQTT, Self-contained Systems, AWS, CircleCI, GitHub, Alexa, Raspberry Pi
Jan 2015 - Dec 2016
1 year Berlin, Germany
Freelance Developer
E-POST Development GmbH
- Java/Scala backend development for a migration project
- Redesigned with scalable REST microservice architecture
- Java SE/EE, Vert.x, Scala, Akka, Cassandra, OAuth, HATEOAS, CQRS
Jan 2015 - Dec 2016
1 year Stuttgart, Germany
Freelance Developer
Sulzer GmbH
- Java/Scala backend development and software architecture
- Java SE/EE, Play, Akka, Scala, REST microservices, JSON, OpenAPI
Jan 2015 - Dec 2015
1 year Berlin, Germany
Freelance Developer
AVM GmbH
- Built a highly available, scalable REST API for encrypted messaging between FRITZ!Box and mobile app
- Java backend development and architecture
- Java SE, Vert.x, MySQL, Redis, Dropwizard, JOSE/JWE, Android
Jan 2015 - Dec 2015
1 year Düsseldorf, Germany
Freelance Developer
Metro Systems
- Java backend development for a global webservice portfolio
- Java EE, Spring/Batch, REST, Groovy, Wildfly, Jersey, PostgreSQL
Jan 2015 - Dec 2015
1 year Münster, Germany
Freelance Developer
viadee Unternehmensberatung
- Modernized a large distributed custom ERP system
- Java SE/EE, EJB, web services, Spring, Hibernate, ESB, EAI, Linux
Jan 2014 - Dec 2015
1 year Frankfurt, Germany
Freelance Developer
Nokia HERE Global B.V.
- Java backend development and architecture
- Scoring, geo-transformation, remoting, search index with Lucene
- Java SE/EE, JSON, REST, Lucene, Hadoop, Kryo, GeoTools, JTS, Elasticsearch, AWS (EC2, S3, EBS, EMR, IAM), RabbitMQ, Linux
Jan 2013 - Dec 2014
1 year Frankfurt am Main, Germany
Freelance Developer
Navteq B.V.
- Java backend development and architecture
- RDF map data acquisition and transformation for geocoding
- Log management, test frameworks, custom Eclipse distribution
- Java SE/EE, JSON, REST, Spring/Batch, Lucene, JTS, Linux, Scrum
Jan 2010 - Dec 2013
2 years Stuttgart, Germany
Freelance Developer/Architect
Nawio GmbH
- Embedded Gentoo Linux on DO160-certified avionics platform
- Complete product development including OS, GUI, network
- Wrote most of the code, including 3D, GPS, terrain, geography
- Java SE, GeoTools, jMonkeyEngine, OpenStreetMap, REST, MQTT
Jan 2009 - Dec 2010
1 year Düsseldorf, Germany
Freelance Developer
Vodafone D2
- Assessed a large ATG-based shop system
- Technical concept and implementation of multiple Wicket apps
Jan 2009 - Dec 2009
1 year Heidelberg, Germany
Freelance Consultant
HMI GmbH
- Architecture, project management and organizational consulting
- Speech understanding system using standard recognizers
- Contributed to competitive presentation at Daimler AG, Stuttgart
- Nuance VoCon, VoiceXML, J2SE, MySQL
Jan 2009 - Dec 2009
1 year Düsseldorf, Germany
Freelance Consultant
Vodafone D2
- Reengineered a large application landscape for internal and external web-based GIS applications
- Detailed specification for transferring the applications
Jan 2009 - Dec 2009
1 year Bonn, Germany
Freelance Consultant
mind Business Consultants
- Consulting on a turnaround project for Deutsche Telekom Value-Added Services Center for multiple speaker identification systems
- Business cases, workshops, architecture, concept creation
- Nuance Recognizer/Verifier, VoiceXML, J2EE
Jan 2008 - Dec 2009
2 years Berlin, Germany
Freelance Developer
Qiro GmbH
- Implemented a J2ME app for a location-based community with server-side positioning and REST clients for Google Local Search, Google Maps and HRS
- Java ME, REST, JSON, Google APIs
Jan 2008 - Dec 2009
1 year Frankfurt, Germany
Freelance Consultant
Deutsche Bahn Systel
- Technical architecture, tender process and vendor selection for implementing a voice portal in a large, distributed VoIP-based call center infrastructure
- VoiceXML, VoIP, SAP BCM/Wicom, Cisco
Jan 2008 - Dec 2009
1 year Hamburg, Germany
Freelance Developer
Navigon / Skobbler
- Architecture reengineering and system specification of the Navi app
- Redesigned the Skobbler app
- Cross-platform design for J2ME, Symbian, BlackBerry, Android
- Coaching for developers in Germany and Cluj/Romania
Jan 2007 - Dec 2008
1 year Cologne, Germany
Freelance Developer
CAP GmbH
- Implemented and rolled out a redesign of a voice application for the customer portal of the HappyDigits bonus program based on VoiceObjects and an ASP-hosted VoiceXML platform
Jan 2007 - Dec 2008
1 year Berlin, Germany
Freelance Developer
Jamba GmbH
- Technical specification and implementation of a global mobile portal infrastructure covering almost all XHTML/WML/J2ME-capable devices
- Integrated UAProf, WURFL, J2MEPolish device databases
Jan 2005 - Dec 2008
2 years Düsseldorf, Germany
Freelance Developer
upside GmbH
- Technical concept and implementation of a web-based marketing information system with PHP for T-Mobile International
- Consulting on architecture and software development process
Jan 2005 - Dec 2006
1 year London, United Kingdom
Freelance Consultant
Ostrich Media Ltd.
- Technical specification, vendor selection, project and partner management for IVR of a high-volume interactive TV format
- Delivered a mission-critical application within six weeks in cooperation with network operator Affiniti
- Tested high call volumes with external VoIP call generator
Jan 2005 - Dec 2006
1 year Bad Homburg, Germany
Freelance Consultant
Strateco GmbH
- Prepared and conducted a workshop on technical and marketing roadmap for speaker identification at T-Online
Jan 2005 - Dec 2006
1 year Dresden, Germany
Freelance Consultant
T-Systems MMS GmbH
- Consulting for Senior EVP Value-Added Services at T-Com
- Comprehensive review of the speech platform portfolio
- Recommendations in the form of a roadmap
Jan 2004 - Dec 2005
1 year Bad Homburg, Germany
Freelance Consultant
Strateco GmbH
- Technical consulting and strategy for building an online development environment for VoiceXML applications in the VOICE Community
- Training, technical articles, developer workshops
Jan 2004 - Dec 2005
1 year Cologne, Germany
Freelance Developer
VoiceObjects AG
- Developed a voice application for automated technical customer support in the T-Com call center based on VoiceObjects and Genesys VoiceXML ASP platform
- Tuning to optimize recognition rates and latency
Jan 2004 - Dec 2006
3 years Hamburg, Germany
Freelance Developer
Navigon GmbH
- Software architecture, development and marketing support to build a navigation system for Java-enabled mobile phones
- Designed the development process and led development of GUI framework, client/server protocol, map-matching algorithm, testing and profiling tools, J2ME Polish
- Created roadmap for future platforms and APIs
- J2ME, J2ME Polish, Navteq, TeleAtlas, OpenStreetMap
Jan 2004 - Dec 2004
1 year Munich, Germany
Freelance Consultant
Euvia Media AG
- Technical consulting and strategy to build various CRM applications supporting business processes in the mass-call IVR system for interactive TV formats
Jan 2004 - Dec 2004
1 year Düsseldorf, Germany
Freelance Developer
VoiceObjects AG and net mobile AG
- Planned and carried out tuning for HP OpenCall VoiceXML platform, Nuance Recognizer, VoiceObjects Server and Cisco SIP/H.323 gateway
Jan 2003 - Dec 2004
2 years Düsseldorf, Germany
Freelance Developer
upside GmbH
- Technical concept and development to build an affiliate webshop for T-Com’s DSL, ISDN and online offers with PHP
Jan 2003 - Dec 2004
1 year Hamburg, Germany
Freelance Consultant
HypoVereinsbank AG
- Project planning, concept, creation and management of the tender at HVB Direkt GmbH to innovate telebanking with voice applications for transfers and other transactions
Jan 2003 - Dec 2004
1 year Düsseldorf, Germany
Freelance Consultant
zefa visual media GmbH
- Project management, analysis, design, developer support as trainer and coach for building web applications for the photo license ordering process of Germany’s third-largest photo agency
Jan 2002 - Present
23 years 7 months Berlin, Germany
Freelance Developer and Consultant
Jan 2002 - Dec 2004
2 years Berlin, Germany
Freelance Developer
Mundwerk AG
- Project lead and lead development on Project LUCY for a telecom client to build an automated dating phone hotline with speech recognition
- Developed a multi-party conference platform
Jan 2002 - Dec 2003
1 year Düsseldorf, Germany
Freelance Developer
conVISUAL AG / Apollis
- Designed and implemented a J2ME application for photos, their album organization and sending via the conVISUAL MMS platform with automatic device adaptation
Jan 1999 - Dec 2003
3 years Berlin, Germany
Co-founder and Technical Director
Mundwerk AG
- First ASP-enabled VoiceXML platform in Europe for internet-based speech recognition over landline and mobile phones
- Co-founded Mundwerk AG, built and led development, operations and support teams of over ten employees
- Acquired and managed suppliers, represented the company at trade shows, conferences and industry events
- Delivered a market-ready product with agile development in six months
- Successful projects for T-Online, Jamba, clever-tanken.de, Viterra Energy Services and Colgate Palmolive
- Supported the trade sale to Excelsis/Almato
Jan 1999 - Dec 2002
2 years Düsseldorf, Germany
Freelance Consultant
conVISUAL AG
- MMB is a platform for mobile messaging apps with SMS/MMS, WAP and other technologies as the basis for conVISUAL’s ASP services
- Analysis and design with an agile developer team after founding, specification and prototype development, coaching and training
- Java EE, WebSphere, UML, WAP, SMS/MMS
Jan 1999 - Dec 2000
1 year Ratingen, Germany
Technical Project Lead
S3 AG
- System architecture and project leadership for creating a web-based Java platform for CRM applications
- Led developer teams in Ratingen, Hamburg and Sofia
Jan 1998 - Dec 2000
3 years Düsseldorf, Germany
Technical Project Lead
NADS GmbH
- Developer and technical project lead of the J2EE-based Pixelboxx product for managing photo/video assets in agencies
- Spun off into an independent company
Jan 1996 - Dec 1998
3 years Dortmund, Germany
Software Developer
NADS GmbH
- Worked with PERL, C/C++ and others for SPD NRW, rational Küchen
Jan 1993 - Dec 1995
2 years Dortmund, Germany
Student Assistant
Chair of AI, Computer Science, University of Dortmund
Summary
My overall goal is to create lasting value for innovations in products and services in telecommunications, IT and other industries by applying proven experience, either as part of a development team or as an independent consultant for technical staff and management. My intrinsic motivation is the joy of building sustainable technical solutions for exciting use cases. I follow a systematic approach and preferably agile methodologies. Alongside my broad generalist knowledge, I have built specific expertise that I particularly enjoy applying in new product and service developments.
Languages
German
Native
English
Advanced
Spanish
Elementary
Education
Oct 1992 - Jun 1999
University of Dortmund
Diploma in Computer Science · Computer Science · Germany · very good
Certifications & licenses
Certified Scrum Master
Scrum Alliance
Brainbench J2EE Master
Brainbench
VoiceObjects
VoiceObjects
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