You're seeing this page as if you were . The main menu is still yours, though. Exit from immersion
Kasim MermerKM

Kasim Mermer

Web, App and Spring Boot Developer

€250/day
Leverkusen, DE
0-2 years

Average response time: 12 hours

Freelancer profile translated to English.
Back to original language

About Kasim

I develop modern web applications, performant backend systems, and cross-platform mobile apps for iOS and Android. My focus is on backend development with Java Spring Boot, particularly on the conception and implementation of stable, secure, and scalable REST APIs that serve as a reliable foundation for web and mobile applications.

Additionally, I create mobile apps with Flutter, enabling the efficient development of high-quality applications for iOS and Android from a common codebase. I place great importance on clean architecture, clear structures, and sustainable, maintainable implementation – from planning to productive deployment.

In addition to technical development, I support companies in becoming visible online. Through targeted SEO optimizations, I improve reach, findability, and user traffic. For one client, I achieved approximately six new customer inquiries per week through a comprehensive SEO overhaul.

Transparency is particularly important to me: No one can guarantee a good Google ranking – Google itself points this out. Successful search engine optimization means consistently implementing proven guidelines, creating technically sound solutions, and continuously improving content to achieve the best possible results.
  • German

    Native or bilingual

  • Turkish

    Native or bilingual

  • English

    Conversational

Can work on-site
Leverkusen (up to 50km)

Experience

  • Selbstständig
    Freelancer - Full-Stack Software Development
    DIGITAL AND IT
    March 2024 - Today (2 years and 5 months)
    Leverkusen, Germany
    • Backend projects for web-based systems and internal tools
    • Development of RESTful APIs with Java (Spring Boot) and PHP (Laravel), user management & DB operations with MySQL
    • Manual testing, code reviews, and active participation in agile
    • processes (Scrum/Kanban)
    • Version control & API testing with GitHub and Postman
    • Tools: IntelliJ IDEA, VS Code, GitHub, Postman, Jira, Trello, MySQL, XAMPP
    Java Spring Boot Search Engine Optimization (SEO) Web Development Back-End Development Software Development
  • New Work Solutions GmbH
    Working Student in Full-Stack Development
    E-COMMERCE
    September 2021 - February 2024 (2 years and 5 months)
    Leverkusen, Germany
    • Backend development for internal tools with Java (Spring Boot, JavaFX)
    • Development of mobile apps with Flutter
    • Creation of RESTful web services for frontend & mobile integration
    • PHP backends for web applications
    • Building and maintaining WordPress websites (including design adjustments)
    • Support in UI/UX design and graphic work
    • Tools: IntelliJ IDEA, VS Code, MySQL, GitHub, Jira, Trello, Postman
    Java Spring Boot Web Development App Development Back-End Development Wordpress
  • MDM-Getränkemarketing GmbH
    Working Student in Java Software Development
    E-COMMERCE
    January 2019 - August 2021 (2 years and 7 months)
    Dortmund, Germany
    • Development and maintenance of internal tools with Java (Spring Boot)
    • Development of internal Android apps (Java / Android Studio)
    • API testing with Postman
    • Tools: IntelliJ IDEA, Postman
    • IT support assistance
    Java Spring Boot Back-End Development Software Development App Development Web Development

Recommendations

Be the first to recommend Kasim

Help this freelancer shine by sharing your experience working together.

These freelancer profiles also match your criteria

AgathaA

Agatha Frydrych

Backend Java Software Engineer

4.7

(3)

2

BaptisteB

Baptiste Duhen

Fullstack developer

4.6

(4)

5

AmedA

Amed Hamou

Senior Lead Developer

4

(2)

7

AudreyA

Audrey Champion

Web developer

4.3

(3)

4

Education

  • Bachelor of Science
    Hamm-Lippstadt University of Applied Sciences
    2025
    Bachelor of Science
  • Bachelor of Science
    South Westphalia University of Applied Sciences
    2018
    Bachelor of Science

Skill set

Categories