LLM Java AI Training Developer

About OpenTrainOpenTrain is the #1 platform for finding and building careers in AI training and data labeling. We connect skilled contributors with opportunities to help develop modern AI systems, build a professional profile, and grow a lasting portfolio of work. As an OpenTrain contractor, you can apply your software development expertise to practical AI projects while gaining experience in model evaluation, dataset creation, and human feedback workflows. Remote contractor opportunityPart-time commitment of 20+ hours per weekWork with English-language AI training tasksBuild experience in software development and AI model improvementAbout AI Training WorkAI training is the human side of building artificial intelligence. People prepare datasets, review model outputs, write and rank responses, evaluate technical accuracy, and provide feedback that helps AI systems become more useful and reliable. This role combines programming with hands-on evaluation work. Your technical judgment will help assess whether model-generated code and responses are clear, relevant, secure, stable, and aligned with defined standards. Support large language model training and evaluationCreate data used for supervised fine-tuningContribute to reinforcement learning with human feedbackHelp improve model quality and ethical behaviorThe RoleOpenTrain is seeking a Java developer to support large language model training, evaluation, and improvement. You will develop backend components while also reviewing model outputs, creating task-specific datasets, and explaining technical decisions clearly. The role is suited to someone who can move between software engineering and structured AI data work. It is listed as entry level and requires 20+ hours per week as a part-time contractor. Core focus: LLM code and response evaluationEmployment type: Part-time contractorExperience level: Entry levelLanguage: EnglishLocation: Worldwide and remoteTime requirement: 20+ hours per weekWhat You'll DoYou will contribute to both the technical implementation and evaluation processes behind AI model improvement. Work should follow explicit quality criteria and support user needs, reliable performance, and ethical model behavior. Design, develop, and maintain efficient Java and backend code used to train and optimize AI models.Build modular web applications with scalable architectures.Conduct model evaluations, benchmark performance, and analyze results for continuous improvement.Evaluate and rank responses to user queries across diverse domains using predefined criteria.Write clear explanations and rationales that demonstrate sound reasoning and technical judgment.Create and maintain high-quality datasets for supervised fine-tuning.Collaborate with researchers and annotators on reinforcement learning with human feedback and reward-model improvement.Develop evaluation strategies that support user needs and ethical model behavior.Create and refine model responses while reviewing code and documentation for quality.Requirements and Helpful BackgroundYou should be comfortable applying modern Java development practices and evaluating technical work against explicit standards. Clear communication is essential because you will need to explain why code or model responses meet, or fail to meet, quality requirements. A bachelor's or master's degree in engineering or computer science is required, or equivalent experience. Prior software quality assurance and test-planning experience is useful, as is experience with large language models, supervised fine-tuning, reinforcement learning with human feedback, or model evaluation workflows. Strong proficiency with Java syntax, conventions, and backend developmentExperience building modular, scalable web applicationsAbility to produce clean, organized, correct, readable, secure, stable, and clearly annotated codeUnderstanding of software testing and quality practicesAbility to evaluate and rank LLM responses against explicit criteriaAbility to explain technical judgments clearlyUnderstanding of supervised fine-tuning, RLHF, and model evaluation workflowsExcellent written and spoken English communicationBachelor's or master's degree in engineering or computer science, or equivalent experienceWhy Build an AI Training CareerAI training and data labeling are among the fastest-growing ways to work in technology. Contributors directly influence how state-of-the-art models write, reason, generate code, and respond to people. The work can be a flexible way to apply specialized skills remotely. Through OpenTrain, you can develop a profile that reflects your AI training experience and use each project to build a stronger long-term portfolio. Work remotely with a computer and internet connectionApply software engineering skills to cutting-edge AI developmentGain practical experience in model evaluation and human feedbackBuild a durable portfolio of AI training work through OpenTrain