Principal ML Researcher (LLM)

Location: European Union; full remote or hybrid if based in the Netherlands or Serbia

Company

hirify.global AI is a well-funded startup that creates data and machine-learning solutions for GenAI models using experts, crowdsourcing, and technology platforms.

What you will do

• Define the multi-quarter technical strategy and architecture for the ML post-training stack.
• Design advanced post-training and reinforcement-learning pipelines using GRPO, PPO, DPO, reward modeling, and RLAIF.
• Build automated evaluation ecosystems with LLM-as-a-judge frameworks, dynamic benchmarks, calibration, and regression controls.
• Lead research in model distillation, quantization, context compression, speculative decoding, and inference optimization.
• Architect autonomous agents and tool-use workflows for multi-step reasoning, self-correction, and evaluation-driven feedback.
• Mentor senior ML researchers and engineers, conduct architecture reviews, and represent research through technical writing and talks.

Requirements

• 6+ years of experience in ML engineering or applied research, including 3+ years leading LLM post-training, fine-tuning, or alignment initiatives at scale.
• Deep practical and theoretical knowledge of SFT, LoRA/PEFT, RLHF/RLAIF, GRPO, DPO, PPO, reward modeling, and reasoning-oriented post-training.
• Experience building evaluation pipelines from scratch and calibrating automated evaluations against human standards.
• Strong Python, PyTorch, distributed training, DeepSpeed, Megatron, FSDP, vLLM, and TensorRT-LLM skills.
• Proven technical leadership, architectural decision-making, mentoring, and cross-functional product influence.
• Fluent written and spoken English at C1 level is required.

Culture & Benefits

• International, dynamic environment focused on innovation in AI and technology.
• Competitive compensation package with base salary, bonus, and ESOP.
• Paid PTO and location-dependent benefits.
• Full remote or hybrid work model, with hybrid available for people based in the Netherlands or Serbia.
• IT setup and home office allowances.