Mario Jelinski

Architect / Developer

Avatar placeholder
Berlin, Germany

Experience

Feb 2025 - Apr 2025
3 months

Architect / Developer

handyhase

  • Overhaul of the entire design and implementation of new UI/UX aspects using React
  • Planning of the software architecture and structuring of the project for long-term scalability using Git for version control
Dec 2024 - Jan 2025
2 months

Mobile Testing & Debugging

  • Developed and maintained automated test scripts for UI and functionality testing using Firebase Test Lab
  • Integrated automated testing into CI/CD pipeline using Git
Apr 2023 - Feb 2024
11 months

Developer

epostbox / compador

  • Optimized digital mail services including printing, PDF conversion, text recognition, and digital signatures
  • Developed a Vue-based training system for accurate address recognition using GPT-4All and proprietary AI models
  • Developed a 5-factor login and authentication system with FIDO2 for secure, passwordless authentication
  • Managed cron jobs with PHP, Node.js, and Java
  • Implemented GraphQL for optimized data queries and comprehensive log analyses
  • Managed SFTP processes in PHP for efficient and secure data exchange
  • Managed ADFS servers and SAML 2.0 and set up internal Git systems with Gitea and pipeline automation
Jan 2023 - Aug 2024
1 year 8 months

Developer

Organ Printing - CNC Modification/Expansion

  • Ported GBRLHal to a 32-bit STM32 microcontroller for enhanced 3D printing capabilities
  • Created a QT QML-based configuration and monitoring interface
Apr 2022 - Dec 2022
9 months

Frontend Developer

Axel Springer SE - upday GmbH

  • Redeveloped the Article Importer app using React and REST API
  • Created a soccer app for the 2022 World Cup featuring events, lineups, statistics, and knockout phase information with extensive testing across mobile devices using Firebase Labs
  • Established robust testing pipelines and Git release pipelines
  • Migrated React-based projects to Angular and Vue
Jan 2022 - Apr 2022
4 months

Fullstack Developer

rapid-data

  • Implemented micro-frontends using Storybook and React
  • Worked with REST APIs, Redux, Recoil, and React-hook-form for efficient data handling
  • Used JUnit and modern CI pipelines for quality assurance
  • Managed codebase with Git and implemented release pipelines
May 2020 - Dec 2021
1 year 8 months

Software Developer / Lead

Auconet GmbH

  • Managed large data imports (SAP, Loga, CSV, XML) into dynamic databases for validation and transformation
  • Rebuilt a legacy Java-based platform to React
  • Automated builds and deployments with Maven and Ant
  • Ensured code quality with JUnit and CI pipelines
  • Maintained code quality and collaboration with Git
Dec 2019 - Apr 2020
5 months

Senior Software Developer

Dive-solutions

  • Built interactive 3D visualizations for fluid simulations using React and Three.js
  • Created scalable, responsive web applications using React and Redux
Nov 2018 - Nov 2019
1 year 1 month

Senior Developer

Cyren GmbH

  • Developed backend solutions for email spam detection using Java and Spring Boot and tested with JUnit
  • Enhanced the Pluto Customer Configuration Platform with React
  • Collaborated using Git for version control
Apr 2016 - Oct 2018
2 years 7 months

Software Developer

Strato AG / 1&1 / IONOS

  • Built and maintained customer platforms including Strato Customer Login, Server Login, and the IONOS product page using Django, JavaScript, and Python
  • Designed responsive UIs with React, Vue, Angular, and Bootstrap
  • Implemented OAuth 2 and Single Sign-On for secure user authentication
  • Improved page speed from 7 seconds to under 950ms
  • Implemented protections against XSS and conducted A/B and Multi-Armed Bandit tests
  • Worked on server cloud solutions with Java and OpenStack
Oct 2013 - Mar 2016
2 years 6 months

Software Developer

eBay

  • Developed and maintained backend and frontend features for Loquo and Alamaula using Java, JavaScript, PHP, Smarty, and CakePHP
  • Conducted SEO optimization and created sandbox environments for SEO testing
  • Implemented error tracking and redirect management using Grafana
  • Optimized search functionality with Elastic Search and managed large-scale data imports for search pages
  • Built responsive interfaces using Prototype and jQuery and optimized page performance
  • Maintained systems on OpenStack with monitoring via Grafana
Apr 2011 - Sep 2013
2 years 6 months

Software Developer

dooyoo (Leguide / Lagardere)

  • Built and enhanced a price comparison platform focusing on scalability and performance
  • Developed CPC calculation and invoicing systems
  • Optimized platform for search engines to improve visibility and traffic
  • Implemented vector-based data mapping for efficient offer matching
  • Designed a custom MVC framework for the platform
  • Analyzed traffic and tracked outgoing clicks for accurate invoicing
Jan 2008 - Dec 2010
3 years

Software Developer

Bardenheuer (Bundesdruckerei)

  • Developed image recognition and processing software for ePass Readers using C, C++, Halcon, Boost, and Qt
  • Created a calibration tool for ePass Readers
  • Collaborated on specifications and performed requirements analysis using UML
  • Developed a PHP-based project management tool to support internal workflows
Jan 2008 - Dec 2008
1 year

Game Developer

LBXGames

  • Created Nintendo DS game mechanics using Assembler, C, and C++
  • Designed and implemented game logic with a custom scripting language
  • Built level editors in C# to streamline game design processes
Jan 2008 - Dec 2008
1 year

Developer

NetworkedAssets

  • Contributed to cable modem design using Java and Perl
  • Conducted performance and stress tests on cable networks
Jan 2007 - Dec 2007
1 year

Working student - IT-Helpdesk

Siemens PG Huttenstraße Gasturbinenwerk Berlin

  • Managed and maintained network infrastructure
  • Configured and deployed hardware and software
  • Conducted monitoring and measurement activities for gas turbines
Jan 2006 - Dec 2006
1 year

Developer / Administration

Siemens PG Huttenstraße Gasturbinenwerk Berlin

  • Developed ERA employee management software
Jan 2005 - Dec 2005
1 year

Student

Charité Berlin / TFH Berlin

  • Developed a smartcard login system for hospitals

Summary

Experienced Software Engineer with a strong focus on Java, Spring Boot, Maven, Ant, Git, React, and Angular. Proven track record in designing and implementing scalable backend and frontend solutions, optimizing build and deployment pipelines, and ensuring high code quality with JUnit and modern CI/CD practices. Adept at collaborating in agile teams and delivering robust software under tight deadlines.

Skills

Core Technologies

  • Java > 10 Years
  • Spring Boot > 6 Years
  • Maven > 8 Years
  • Ant > 7 Years
  • Junit > 8 Years
  • Git > 10 Years
  • React > 6 Years
  • Angular > 6 Years

Programming Languages & Frameworks

  • Javascript > 10 Years
  • Java > 10 Years
  • C++ > 5 Years
  • Php > 8 Years
  • Python > 6 Years
  • React > 5 Years
  • Vue > 4 Years
  • Angular > 5 Years
  • Node.js > 6 Years
  • Kotlin > 3 Years
  • Spring Boot > 5 Years
  • Hibernate > 5 Years
  • Typescript > 5 Years
  • Three.js > 4 Years
  • Phaser > 3 Years

Web-server And Infrastructur

  • Apache > 8 Years
  • Nginx > 6 Years
  • Docker > 6 Years
  • Kubernetes > 4 Years
  • Aws > 6 Years

Monitoring And Performance-tools

  • Grafana > 5 Years
  • Prometheus > 4 Years
  • New Relic > 3 Years
  • Datadog > 4 Years

Authentication & Security

  • Oauth2 / Openid Connect > 6 Years
  • Jwt (Json Web Token) > 5 Years
  • Single Sign-on (Sso) > 5 Years

Databases

  • Mysql > 10 Years
  • Postgresql > 8 Years
  • Mongodb > 6 Years

Version Control & Project Management

  • Git > 10 Years
  • Jira > 8 Years
  • Asana > 5 Years

Testing

  • Unit Testing (Jest, Junit, Pytest, Etc.) > 8 Years
  • Integration Testing > 6 Years
  • End-to-end Testing (Cypress, Selenium) > 5 Years
  • Test Automation / Ci Pipelines > 6 Years

Languages

German
Native
English
Advanced

Education

Oct 2008 - Jun 2010

Beuth University of Applied Sciences Berlin

Master of Engineering · Embedded Systems · Berlin, Germany

Oct 2003 - Jun 2007

Technical University of Applied Sciences Berlin

Diploma Engineer · Technical Computer Science Real-Time Systems · Berlin, Germany

Oct 2000 - Jun 2003

Lette Association (Public Law Foundation)

State-Certified Assistant for Electronics and Data Technology · Electronics and Data Technology · Berlin, Germany

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

Similar Freelancers

Discover other experts with similar qualifications and experience

Peter Kortmann
Peter Kortmann

Hardware and Software Developer / Project Manager

View Profile
Olaf Nouvortne
Olaf Nouvortne

Frontend Engineer

View Profile
Dieter Möhrle
Dieter Möhrle

Software Engineer

View Profile
Adam Richter
Adam Richter

Senior Software Engineer

View Profile
Jan Mönnich
Jan Mönnich

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

View Profile
Ulf Schiebener
Ulf Schiebener

Innovation Manager

View Profile
Patrick Eichler
Patrick Eichler

Kubernetes Expert | Google Cloud Platform Engineer

View Profile
Matthias Eymers
Matthias Eymers

Lead Android Developer

View Profile
Marian Gaebler
Marian Gaebler

Senior Software Engineer

View Profile
Olaf Titel
Olaf Titel

CTO, Partner, Agile Coach, Product Owner

View Profile
Thomas Stägemann
Thomas Stägemann

Rating System

View Profile
Piet Althoff
Piet Althoff

Frontend

View Profile
Sven Koebnick
Sven Koebnick

All-round admin

View Profile
Alexis Peters
Alexis Peters

Freelance Team Lead Backend Applications E-Commerce

View Profile
Michael Kraft
Michael Kraft

Co-Founder

View Profile
Noël Lohrey
Noël Lohrey

Freelance Senior Product Owner

View Profile
Philipp Eick
Philipp Eick

Project Lead | Infotainment Software Architecture and Special Hardware Agricultural Machinery

View Profile
Werner Keil
Werner Keil

Test Coordinator, Designer and Engineer

View Profile
Sebastian Nkwenti
Sebastian Nkwenti

Test Manager: MW/OS Interlocking (Railway Interlocking Systems)

View Profile
Arne Hendricks
Arne Hendricks

Embedded Fullstack Developer

View Profile
Kai Schmudlach
Kai Schmudlach

Software Developer

View Profile
Torsten Glunde
Torsten Glunde

BI consultant

View Profile
André Görst
André Görst

IT Consulting Project Management / Engineering Subproject Management

View Profile
Jonas Dittrich
Jonas Dittrich

CEO

View Profile
Andreas Fischer
Andreas Fischer

Project Manager & Portfolio Owner for Infrastructure (Automotive)

View Profile
Rüdiger Schulz
Rüdiger Schulz

Full-Stack Software Engineer / Consultant for Digitalization

View Profile
Jürgen Brardt
Jürgen Brardt

Software Developer

View Profile
Volker Ahlers
Volker Ahlers

Fullstack Developer

View Profile
Finn Hinrichsen
Finn Hinrichsen

Data Architecture

View Profile
Denis Vodchyts
Denis Vodchyts

AUTOSAR Software Engineer

View Profile