Senior Backend Developer

Market Calculus Türkiye; Çankaya; On-site; TRY 500,000 - 780,000; Full time

Job summary

Market Calculus Türkiye is seeking an experienced Senior Backend Developer to own the design, build, and evolution of scalable backend systems using Java and the Spring ecosystem.

You will collaborate with product, frontend, QA, DevOps, and other engineering teams to deliver reliable software. The role emphasizes end-to-end ownership and applying modern AI-assisted development tools while ensuring code quality and maintainability.

Qualifications

• 6+ years of professional software development experience.
• Proficient in Java and Spring Boot with OO design and patterns.
• Strong RESTful API design, SQL and relational databases.
• Experience with JUnit and Mockito; automated testing mindset.
• Git-based collaboration and Linux command-line proficiency.
• Excellent English communication and ownership in fast-moving teams.
• Experience using AI coding assistants in the development lifecycle.

Responsibilities

• Design, develop, test, deploy, and maintain scalable backend services in Java/Spring.
• Own backend features from design through production operation.
• Contribute to architecture, API design, data models, and decisions.
• Design integrations with internal and external systems.
• Write clean, well-tested code and refactor for quality.
• Build and maintain unit/integration/API tests.
• Review designs and mentor junior developers.
• Diagnose production issues using logs and metrics.
• Improve performance, scalability, reliability, and security.
• Collaborate with frontend, QA, DevOps, and product teams.
• Leverage AI-assisted tools for coding, refactoring, testing.

Skills

Java

REST APIs

SQL

JUnit/Mockito

Git workflows

English comms

Ownership

AI coding tools

Tools

Spring Boot

Spring Data

Spring MVC

JPA/Hibernate

Docker

Kubernetes

Maven

Redis

Kafka

RabbitMQ

GitHub Actions

Job description

About the Role

We are looking for an experienced Senior Backend Developer to join our engineering team and take ownership of designing, building, and evolving scalable backend systems.

You will work primarily with Java and Spring Boot, contribute to architectural decisions, and collaborate closely with product, frontend, QA, DevOps, and other engineering teams to deliver reliable and maintainable software.

We expect senior engineers not only to write high-quality code, but also to understand the systems they build end-to-end, make sound technical decisions, improve engineering practices, and make effective use of modern AI and agentic development tools.

Key Responsibilities

• Design, develop, test, deploy, and maintain scalable backend services using Java and the Spring ecosystem.


• Take ownership of backend features and services from technical design through production operation.


• Contribute to system architecture, API design, data models, and technical decision-making.


• Design reliable integrations with internal and external systems and services.


• Write clean, maintainable, well-tested code and continuously improve existing codebases through thoughtful refactoring.


• Build and maintain automated tests, including unit, integration, and API-level tests.


• Review code and technical designs, provide constructive feedback, and mentor less experienced developers.


• Diagnose and resolve production issues using logs, metrics, traces, and other observability tools.


• Improve system performance, scalability, reliability, security, and operational efficiency.


• Collaborate closely with frontend developers, QA engineers, DevOps engineers, product teams, and other stakeholders.


• Use modern AI-assisted and agentic development tools effectively for tasks such as implementation, refactoring, codebase exploration, testing, debugging, documentation, and technical analysis.


• Review and validate AI-generated code and solutions with the same engineering rigor applied to human-written code.


• Continuously evaluate new development tools and practices that can improve engineering quality and team productivity.

Required Qualifications

• 6+ years of professional software development experience, with substantial experience building backend systems.


• Strong proficiency in Java and a solid understanding of object-oriented design, clean code principles, and common software design patterns.


• Strong hands-on experience with Spring Boot and relevant Spring technologies such as Spring Data and Spring MVC.


• Solid experience with JPA/Hibernate or similar persistence technologies.


• Strong understanding of RESTful API design, HTTP, authentication, authorization, and integration patterns.


• Strong knowledge of SQL and relational databases, preferably PostgreSQL or similar production-grade database systems.


• Good understanding of transactions, concurrency, database performance, and data modeling.


• Experience designing and operating production backend systems with attention to performance, scalability, reliability, and fault tolerance.


• Practical experience with automated testing using tools such as JUnit, Mockito, and integration-testing frameworks.


• Strong proficiency with Git and modern collaborative development workflows based on branches, pull requests, and code reviews.


• Comfortable working with Linux-based environments and command-line tools.


• Experience investigating production problems using logging, monitoring, metrics, and tracing.


• Ability to understand an existing codebase, identify architectural and technical issues, and propose pragmatic improvements.


• Practical experience using AI coding assistants or agentic development tools as part of the software development lifecycle.


• Ability to critically review, test, and validate AI-generated implementations rather than relying on generated output without verification.


• Strong written and verbal communication skills in English.


• Strong sense of ownership and ability to work effectively in a fast-moving product development environment.

Preferred Qualifications

• Experience designing distributed systems, microservices, and event-driven architectures.


• Experience with messaging and streaming technologies such as Kafka or RabbitMQ.


• Experience with Docker, Kubernetes, or similar container and orchestration technologies.


• Experience with cloud platforms such as AWS, Google Cloud, or Azure.


• Experience with CI/CD platforms such as GitHub Actions, GitLab CI, Jenkins, or similar tools.


• Experience with build and dependency management tools such as Maven.


• Familiarity with observability platforms and concepts including structured logging, metrics, distributed tracing, and alerting.


• Understanding of application and API security principles.


• Experience with caching technologies such as Redis.


• Experience working with high-volume or data-intensive backend systems.


• Familiarity with LLM APIs, tool/function calling, MCP, agentic workflows, or AI-enabled backend applications is a plus.


• Experience improving engineering workflows using AI-assisted development, automated code review, or agent-driven testing is a plus.

What We Value

• Take ownership instead of waiting for detailed instructions.


• Think about the system as a whole rather than only the code they are currently working on.


• Prefer simple, pragmatic solutions over unnecessary complexity.


• Can balance engineering quality with the need to deliver.


• Question assumptions and contribute constructively to technical decisions.


• Use AI and automation to increase productivity while maintaining responsibility for the quality of the final result.


• Enjoy learning new technologies and adapting their development practices as software engineering evolves.