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David Sumegi
Verified Expert in Engineering
Software Developer
Budapest, Hungary
Toptal member since January 5, 2021
Bio
Backed by several years of hands-on experience, David is a software developer who excels at building Java back-end services, relational databases, and software architecture. His solid testing background makes him the type of developer who prevents incidents early on via automated tests with 100% code coverage. David is also an enthusiast of SOLID principles, clean code, clean architecture, and design patterns.
Portfolio
Global Blue
Spring Microservice, Spring Boot, Microservices, RESTful Services...
FedEx
Java, Spring WebFlux, Reactor, Spring, PostgreSQL, Lombok, Spring Boot, Azure...
SwissRe iptiQ - Main
Java, Spring, SOLID Principles, NoSQL, Relational Databases, Unit Testing...
Experience
- Java - 10 years
- Git - 8 years
- Microservices - 8 years
- RESTful Development - 8 years
- SQL - 7 years
- Back-end - 6 years
- Spring - 6 years
- Spring Boot - 6 years
Work Experience
Senior Software Developer
2025 - PRESENT
Global Blue
- Implemented traveller data management functionalities behind global tax refunding services.
- Provided quality assurance by building extensive automated service test suites covering all features.
- Restructured microservice code to a multi-module clean project structure with clean business logic.
Technologies: Spring Microservice, Spring Boot, Microservices, RESTful Services, RESTful Microservices, Java, Microsoft SQL Server, Apache Maven, RabbitMQ, Spring Data JPA, Development, Code Review, Test Automation, RESTful Development, Relational Databases, Test Automation Frameworks, HTML, JDBC, Unit Testing, CSS, APIs, Bitbucket, Back-end, JSON, Object-oriented Programming (OOP), API Design, Software Architecture, Web Services, REST APIs, REST, Architecture
Back-end Developer
2022 - 2024
FedEx
- Added eCommerce capabilities to the shipment management system.
- Implemented API integrations to external aggregation services and eCommerce platforms.
- Participated in architectural changes, such as splitting a monolith service into microservices.
Technologies: Java, Spring WebFlux, Reactor, Spring, PostgreSQL, Lombok, Spring Boot, Azure, Kubernetes, GitHub, eCommerce, API Integration, Spring Data JPA, Docker, APIs, Apache Kafka, Test Automation, Microservices, RESTful Development, Relational Databases, Test Automation Frameworks, Unit Testing, Gradle, Code Review, Development, Spring Microservice, CSS, Back-end, JSON, Object-oriented Programming (OOP), API Design, RESTful Microservices, Software Architecture, Web Services, REST APIs, REST, Architecture
Java Developer
2021 - 2021
SwissRe iptiQ - Main
- Prepared back-end services for an upcoming migration to a different platform provider.
- Collected and analyzed information to determine data models for the conversion of migrated data.
- Supported data analysts by generating schema files.
Technologies: Java, Spring, SOLID Principles, NoSQL, Relational Databases, Unit Testing, Code Review, Development, Back-end, JSON, Object-oriented Programming (OOP)
Software Contractor
2021 - 2021
Latch
- Refactored and extended middleware functions syncing property and resident information from external property management systems.
- Increased observability of back-end processes by adding Datadog metrics and monitors to service and daemon applications.
- Created detailed documentation on the existing business logic as well as the new features.
Technologies: Java, Databases, Git, Bitbucket, IntelliJ IDEA, Spring, Back-end, Gradle, Amazon Web Services (AWS), JUnit, RDBMS, RESTful Services, APIs, Relational Databases, Unit Testing, Code Review, Development, JSON, Object-oriented Programming (OOP)
Senior Back-end Developer
2019 - 2021
Bankmonitor
- Introduced new calculators to Bankmonitor's market-leading independent public website comparing banking services.
- Migrated Java 8 monolith services to scalable Spring Boot microservices using Java 11 running on Amazon Elastic Kubernetes Service.
- Optimized the performance of back-end systems to minimize response times and handle an increasing load of requests.
Technologies: Back-end, JSON, Unit Testing, Object-oriented Programming (OOP), Lombok, API Design, RESTful Microservices, Spring JDBC, JDBC, REST, REST APIs, Web Services, Architecture, Clean Code, Design Patterns, Software Architecture, Apache Maven, MySQL, SQL, Relational Databases, Git, RESTful Development, Microservices, Spring Boot, Spring, Bitbucket, Databases, Fintech, Amazon Web Services (AWS), Microservices Architecture, JUnit, RDBMS, RESTful Services, Hibernate, APIs, Code Review, Development, Spring Microservice
Java Developer
2020 - 2020
Mana Monitoring
- Established synchronization between MySQL and Apache Cassandra databases storing solar energy billing information.
- Created a bill uploading and parsing function with a web user interface for clients.
- Implemented a reporting tool collecting and comparing billing data originating from different sources for the same site.
Technologies: Back-end, JSON, Unit Testing, Object-oriented Programming (OOP), Lombok, Spring JDBC, JDBC, Architecture, Software Architecture, Design Patterns, Clean Code, API Design, RESTful Microservices, Microservices, Apache Maven, Git, Spring, Spring Boot, SQL, MySQL, Relational Databases, Web Services, RESTful Development, REST APIs, REST, Java, Databases, JUnit, RDBMS, RESTful Services, Code Review, Development
Java Web Developer
2017 - 2019
BlackRock
- Built a new web-based version of an old portfolio management application while cooperating closely with front-end developers and key users.
- Integrated artificial intelligence into the existing document management system while working with machine learning and NLP experts.
- Acted as a lead developer within the local sub-team of developers and data scientists.
Technologies: Back-end, JSON, Unit Testing, Object-oriented Programming (OOP), Lombok, API Design, RESTful Microservices, Spring JDBC, JDBC, Hibernate, REST, REST APIs, Web Services, Architecture, Software Architecture, Design Patterns, Clean Code, Java, Apache Maven, SQL, Relational Databases, Git, Spring Boot, Spring, RESTful Development, Microservices, Bitbucket, Databases, IntelliJ IDEA, Fintech, Microservices Architecture, JUnit, RDBMS, RESTful Services, Java 8, APIs, Code Review, Development, Spring Microservice
Software Developer
2014 - 2017
Morgan Stanley
- Upgraded legacy stock loan management systems with modern microservices.
- Added search and cache layers to systems that were tracking financial transactions.
- Improved data access performance by optimizing database queries and configurations.
Technologies: Back-end, JSON, Unit Testing, Object-oriented Programming (OOP), Lombok, API Design, RESTful Microservices, Spring JDBC, JDBC, REST, REST APIs, Web Services, Architecture, Software Architecture, Design Patterns, Clean Code, Java, Apache Maven, Microservices, RESTful Development, SQL, Relational Databases, Spring Boot, Spring, Git, Databases, IntelliJ IDEA, Fintech, Microservices Architecture, JUnit, RDBMS, RESTful Services, Hibernate, Java 8, APIs, Test Automation Frameworks, Code Review, Development, Spring Microservice
Senior Test Automation Engineer
2013 - 2014
NNG
- Built an automation framework for testing navigation systems of Fiat, Ferrari, and Toyota cars.
- Implemented nightly jobs to receive and validate operating system updates sent by Harman.
- Defined standard processes for project management to track validation requirements and release results.
Technologies: HTML, Test Automation Frameworks, CSS, Test Automation, Relational Databases
System Test Engineer
2011 - 2013
Bosch
- Built test plans for the next-generation video-based driver assistance systems of Audi, Porsche, and Volkswagen cars.
- Automated 98% of manual test sets for selected areas of image detection functions.
- Designed and deployed a visual simulation tool using a controllable OLED display to support lab testing of camera features.
Technologies: Test Automation Frameworks, Test Automation
Software Engineer
2007 - 2010
Nokia Siemens Networks
- Started as a university student composing my thesis on software test automation principles and techniques.
- Fixed bugs and extended regression test suites continuously to prevent incidents.
- Implemented new methods inside the test automation framework using Perl scripts.
Technologies: Test Automation Frameworks, Test Automation
Project History
Online E2E Contracting for Bank Customers (CIB)
https://www.bankmonitor.hu/Worked as the back-end engineer on this project in cooperation with Bankmonitor—Hungary's market-leading independent online bank product broker— and CIB to enable retail customers to open a new bank account anytime without speaking with a dispatcher.
My tasks involved the API integration of several systems, including a third-party video authentication provider. I covered the whole software lifecycle, from analyzing the business requirements to deployment and end-user support.
My tasks involved the API integration of several systems, including a third-party video authentication provider. I covered the whole software lifecycle, from analyzing the business requirements to deployment and end-user support.
Aladdin Document Repository (BlackRock)
Added automatic OCR and metadata cleansing functions to an existing document management system. Furthermore, I extended the repository with an AI feature created by data scientists that used natural language processing to extract specific data from the files' text content.
eCommerce Capabilities Project for FedEx
http://www.fedex.comParticipated in a project that enables eCommerce merchants to connect their stores with the FedEx shipment management system so that they import their orders and have all shipment information filled automatically,
Education
2002 - 2008
Master's Degree in Electrical Engineering
Budapest University of Technology and Economics (BME) - Budapest, Hungary
Skills
Libraries/APIs
REST APIs, JDBC, Lombok, Reactor
Tools
Git, Apache Maven, Bitbucket, IntelliJ IDEA, Gradle, GitHub, RabbitMQ
Languages
Java, SQL, HTML, Java 8, CSS
Frameworks
Spring JDBC, Spring, Spring Boot, Hibernate, JUnit, Spring WebFlux, Spring Microservice
Paradigms
REST, Object-oriented Programming (OOP), Unit Testing, RESTful Development, Test Automation, Microservices, Design Patterns, Clean Code, Microservices Architecture
Storage
MySQL, JSON, RDBMS, Relational Databases, Spring Data JPA, MongoDB, Databases, Redis, NoSQL, PostgreSQL, Microsoft SQL Server
Platforms
Amazon Web Services (AWS), Azure, Kubernetes, Docker, Apache Kafka
Other
Test Automation Frameworks, Architecture, Software Architecture, API Design, Back-end, Fintech, RESTful Services, Web Services, RESTful Microservices, eCommerce, APIs, SOLID Principles, API Integration, Development, Code Review
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