Machine Learning Research Engineer

We are hiring a Research Engineer to own the improvement loop for a research engine we are building on top of the Seqera Platform. You will build the data and evaluation flywheel from engine’ own run data, and use it to post-train small, task-specific models that make it better at generating, ranking and running scientific ideas. You will work directly with our Founding Scientist and the engineers who own the application, on a small team that moves fast and ships to real scientists. This is an in-office role in Barcelona. The team is here, the whiteboards are here, and this is the kind of work that goes faster in the same room., * Design and build the evaluation suite that defines what “better” means for an autonomous research agent.

• Build the pipeline that turns messy, real-world run data from deployments into a training-ready corpus.
• Post-train small open-weight models - SFT, preference tuning, adapters - to beat frontier-API baselines on core tasks at lower cost and latency.
• Run repeated training cycles on evolving data.
• Participate in journal clubs, stay at the frontier of post-training specialized models.
• Own the Next-Gen roadmap with our Founding Scientist: what data unlocks what capability, and in what order., * You have retrained models on changing data more than once and have dealt with regression and forgetting in practice: replay, data mixing, adapter strategies, eval gating.
• You have built evaluation harnesses for a specific task, defined the metric yourself, and defended the result to someone sceptical.
• You work fluently in Python with the modern stack - PyTorch, transformers, TRL, PEFT, vLLM or their equivalents.
• Your open-source footprint speaks for you: substantive contributions to the tools above, or fine-tuned models on the Hub.
• You are an operator. When the pipeline you need does not exist, you build it. You are comfortable when the data, the tooling and the direction are all incomplete at the same time.
• You want to work in-office in Barcelona, or you are ready to move here.

• You have post-trained open-weight language models - SFT and at least one preference-tuning method - and put the results in front of real users, not just in a notebook., * Computational biology, chemistry or pharma exposure.
• Familiarity with Nextflow or workflow orchestration.
• Experience evaluating agentic, multi-step, tool-using systems.
• Distillation or small-model specialisation from frontier models.
• Publications or technical reports in post-training or continual learning.

• Flexible working hours.
• International working environment with more than 25 nationalities.
• Passionate & talented team.
• Continuous skills development.
• Team retreats and bonding activities.
• A culture where your opinion is valued and your decisions have a real impact on the industry.
• Excitement of a fast-growing startup in a constantly changing environment.

Great benefits

• Time off: 23 days for vacations per year, 3 days given by Seqera in December, and the national/public holidays according to your location.
• Equity
• Private health insurance
• Private life insurance
• Home office allowance (valued over 1,000 USD)
• Subscription to Oliva, Mental Health App
• Learning and development budget per year (1,000 USD)