Senior AI Scientist

About the role

Workster is partnering with an innovative AI startup to build autonomous agents that can run code, self‑repair, and analyse data. As a Senior AI Scientist you will own end‑to‑end research and production pipelines, turning cutting‑edge concepts into reliable products.

Key responsibilities

• Lead research, prototyping and development of agentic LLM features from proof‑of‑concept to production.
• Design scalable architectures such as modular LLMs and Mixture‑of‑Experts.
• Oversee the full model lifecycle: data ingestion, training, validation, deployment and monitoring.
• Integrate autonomous capabilities like code execution, structured memory and toolformer‑style API calls.
• Collaborate with engineering to deploy via Ray, Kubernetes and CI/CD pipelines.

Required profile

• Deep expertise in transformers, attention mechanisms and fine‑tuning.
• Strong background in reinforcement learning (RLHF, reward modelling) and AI alignment, safety or interpretability.
• Proven ability to lead research projects and mentor junior team members.
• Track record of delivering AI features from concept to production.
• Impact and leadership valued over formal degree requirements.

Required skills

• Python (advanced)
• PyTorch
• Distributed training, quantised inference, batching and caching
• Ray, Kubernetes, CI/CD for ML
• Modular LLM design, Mixture‑of‑Experts

What we offer

• Hybrid work in Lisbon with multi‑week remote blocks.
• Competitive senior‑level salary plus equity.
• Subsidised apartment for relocation.
• Health insurance, modern hardware and personal learning budget.
• Company‑funded travel to global AI conferences.