Freelance Software Developer (Java) - Quality Assurance / AI Trainer

Mindrift; Polska; Remote; PLN 180,000 - 240,000; Part time

Job summary

A technology firm specializing in AI is seeking a Freelance Software Developer to contribute to innovative projects. The role requires expertise in Java 17+ and a strong understanding of testing frameworks and CI/CD tools. This is a fully remote opportunity, with rates up to $47/hour based on skills and experience. Join us to advance AI capabilities and work on cutting-edge developments in the field.

Benefits

Flexible working hours

Competitive pay based on expertise

Work on advanced AI projects

Qualifications

• Minimum 3 years of experience in Java, including streams API and concurrent programming.
• Advanced (C1) level of English.
• Hands-on experience with testing frameworks and CI/CD tools.

Responsibilities

• Code generation and code review.
• Training and evaluation of large language models.
• Collaborate on complex projects with various stakeholders.

Skills

Java 17+

JUnit 5

TestNG

Mockito

TestContainers

Maven

Gradle

Spring Boot

Spring Data

Spring Security

Kafka

RabbitMQ

AWS

Azure

Kubernetes

Education

Bachelor's or Master's Degree in Computer Science or related fields

Tools

IntelliJ IDEA

Jenkins

GitHub Actions

GitLab CI

JProfiler

VisualVM

Job description

Freelance Software Developer (Java) - Quality Assurance / AI Trainer

This opportunity is only for candidates currently residing in the specified country. Your location may affect eligibility and rates. Please submit your resume in English and indicate your level of English proficiency.

At Mindrift, innovation meets opportunity. We believe in using the power of collective intelligence to ethically shape the future of AI.

What We Do

The Mindrift platform connects specialists with AI projects from major tech innovators. Our mission is to unlock the potential of Generative AI by tapping into real-world expertise from across the globe.

About The Role

GenAI models are improving very quickly, and one of our goals is to make them capable of addressing specialized questions and achieving complex reasoning skills. If you join the platform as an AI Tutor in Coding, you'll have the opportunity to collaborate on these projects.

Although every project is unique, you might typically:

• Code generation and code review
• Prompt evaluation and complex data annotation
• Training and evaluation of large language models
• Benchmarking and agent-based code execution in sandboxed environments
• Working across multiple programming languages
• Adapting guidelines for new domains and use cases
• Following project-specific rubrics and requirements
• Collaborating with project leads, solution engineers, and supply managers on complex or experimental projects

Note: Flexibility and quick adaptation to new requirements are essential.

How To Get Started

Simply apply to this post, qualify, and get the chance to contribute to projects that match your technical skills, on your own schedule. From coding and automation to fine-tuning AI outputs, you'll play a key role in advancing AI capabilities and real-world applications.

Requirements

• You hold a Bachelor's or Master's Degree in Computer Science, Software Engineering, Software Development, Computer Engineering, Mobile App Development, Cloud Computing, Data Science, Big Data or other related fields
• You have at least 3 years of professional experience in Java 17+, including streams API and concurrent programming
• Your level of English is advanced (C1) or above
• Hands‑on experience with JUnit 5, TestNG, Mockito, and TestContainers
• Proficiency with build tools (Maven, Gradle), IDEs (IntelliJ IDEA), and CI/CD pipelines (Jenkins, GitHub Actions, GitLab CI)
• Experience with the Spring ecosystem (Spring Boot, Spring Data, Spring Security), JPA/Hibernate
• Strong understanding of JVM internals, garbage collection, performance optimization, and design patterns
• Experience with messaging systems (Kafka, RabbitMQ) and microservices architectures
• Practical use of AI‑assisted tools for refactoring, performance analysis, and test generation
• Familiarity with cloud platforms (AWS, Azure), containers, and Kubernetes
• Strong skills in JVM profiling (JProfiler, VisualVM) and debugging
• You are ready to learn new methods, able to switch between tasks and topics quickly and sometimes work with challenging, complex guidelines
• Our freelance role is fully remote so, you just need a laptop, internet connection, time available and enthusiasm to take on a challenge

Benefits

Why this freelance opportunity might be a great fit for you?

• Get paid for your expertise, with rates that can go up to $47/hour depending on your skills, experience, and project needs
• Take part in a part-time, remote, freelance project that fits around your primary professional or academic commitments
• Work on advanced AI projects and gain valuable experience that enhances your portfolio
• Influence how future AI models understand and communicate in your field of expertise