Costin Oncioiu-Java Developer
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Experience
Java Developer
Eucon Gmbh
- Use my knowledge to design the domain of the platform aligning with the business objectives
- Implemented robust authentication and authorization system in a dynamic multi-tenant environment
- Coded the business layer logic, using the best software development standards in the industry including quality gates and testing coverage
- Continuously contributed to creating a maintainable architecture that fits the product expansion plans based on the business needs
Java Developer - Spring Boot
Coherent Solutions
- Created the business logic that helps configure client advertising campaigns and aggregates data into reports for the UI team
- Created a business layer from scratch with various microservices and used AWS to facilitate communication between them
- Built a wrapper over company SSO to add security and enable authentication and authorization
- Enhanced application performance to ensure fast responses despite large data loads
- Participated in architecture design, domain modeling, splitting business logic across microservices, designing lambdas, analyzing and optimizing dataflow
- Owned different parts of the project and improved, solved problems, and helped teammates interact with them
Fullstack Java Developer
Jouve International
- Developed new features and extended existing ones for a financial reports and proxy statements platform resembling Google Sheets
- Analyzed client requirements and delivered high-quality solutions
- Built authentication and authorization mechanisms
- Adjusted application to enhance performance
- Took interviews with newcomers and integrated them into the team
- Performed backend work and contributed to some frontend development
Fullstack Java Developer
Artsoft Consult
- Developed B2B software used by leading global telecommunication companies with fast and efficient responses
- Contributed to resource management platform and connector interface for payment, billing, stocks, and shop connections for a major machinery manufacturer
- Optimized parallel processing code to increase efficiency, readability, and predictability
Software Engineer
Micro Focus
- Worked on a platform for full server management of thousands of servers
- Integrated new operating systems into the system
- Improved old components and developed new ones
Web Developer
TSS-YONDER
- Developed a large management platform for employee management of schools and utility companies
- Implemented features based on requirement analysis and clarified requirements with the customer
Android Intern
Halcyon Mobile
Industry experience
See where this freelancer has spent most of their professional time.
Experienced in Information Technology, Manufacturing, Telecommunication, Advertising, Education, and Utilities.
Business area experience
See which departments and functions this freelancer has contributed to most.
Experienced in Information Technology, Product Development, Quality Assurance, Finance, Supply Chain Management, and Human Resources.
Summary
I'm a Senior Java developer/engineer with 6.5 years of hands-on software development and experience collaborating with worldwide companies. My expertise includes all layers of the development process from database design and business logic to front-end software implementation and deployment. Easily integrable in any team, I played an important role throughout my career helping my teams deliver high quality, future proof software products.
Skills
Backend:
- Java Core, Spring Framework, Spring Boot
- Spring Security, Jwt, Oauth2
- Hibernate, Jpa, Spring Data
- Rest, Hateoas
- Postgresql, Mongodb, Mysql, Liquibase, Flyway
- Junit, Mockito, Spock (Groovy)
Cloud:
- Aws, Lambda, S3, Sqs, Eventbridge, Ec2, Cloudwatch
Other:
- Maven, Git, Bitbucket, Jira
- Sonarqube, Jenkins, Docker, Kubernetes
- Microservices Architecture, Layered Architecture, Event-Driven Architecture
- Design Patterns, Solid Principles, Clean Code, Kiss
Frontend:
- Angular, Typescript
- Angular Material, Bootstrap
- Html, Css, Javascript, Jquery
Languages
Education
Faculty of Mathematics and Informatics, Babes-Bolyai University of Cluj-Napoca
Master in Software Engineering, Event-Driven Microservices with CQRS and Event Sourcing · Software Engineering · Cluj-Napoca, Romania
Faculty of Mathematics and Informatics, Babes-Bolyai University of Cluj-Napoca
Bachelor in Computer Science, Cross platform mobile faculty timetable using cloud web scrapping · Computer Science · Cluj-Napoca, Romania
Statistics
Experience
Global experience
Expertise
Qualifications
Profile
Frequently asked questions
Have questions? Find more information here.
Costin is based in Cluj-Napoca, Romania.
Costin speaks the following languages: English (Advanced), Romanian (Advanced).
Costin has at least 8 years of experience. During this time, Costin has worked in at least 6 different roles and for 7 different companies. The average length of individual experience is 1 year and 2 months. Note that Costin may not have shared all experience and actually has more experience.
Based on recent experience, Costin would be well-suited for roles such as: Java Developer, Java Developer - Spring Boot, Fullstack Java Developer.
Costin's most recent position is Java Developer at Eucon Gmbh.
In recent years, Costin has worked for Eucon Gmbh and Coherent Solutions.
Costin is most experienced in industries like Information Technology, Manufacturing, and Telecommunication. Costin also has some experience in Advertising, Education, and Utilities.
Costin is most experienced in business areas like Information Technology, Product Development, and Quality Assurance. Costin also has some experience in Finance, Supply Chain Management, and Human Resources.
Costin has recently worked in industries like Information Technology and Advertising.
Costin has recently worked in business areas like Information Technology, Product Development, and Quality Assurance.
Costin holds a Master in Software Engineering from Faculty of Mathematics and Informatics, Babes-Bolyai University of Cluj-Napoca and a Bachelor in Computer Science from Faculty of Mathematics and Informatics, Babes-Bolyai University of Cluj-Napoca.
The availability of Costin needs to be confirmed.
Daily rate distribution
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Average rates for similar positions
Rates are based on recent contracts and do not include FRATCH margin.
The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.
The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.
Calculated based on our freelancers’ daily rates as of 25 Aug 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
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