Senior Staff Research Scientist

DeepL; City Of London; Hybrid; GBP 80,000 - 110,000; Full time

Job summary

A leading technology company in London seeks a Senior Staff Research Scientist to lead groundbreaking research in reinforcement learning. You will define scientific strategies, mentor researchers, and deploy advanced models at scale. Join a globally diverse team that values clear communication and innovative thinking while offering a hybrid work environment and competitive benefits. Embark on a career journey in the AI industry with us.

Benefits

30 days annual leave

Hybrid work schedule

Monthly hack sessions

Competitive benefits

Qualifications

• 5+ years of experience in ML research, leading high-impact projects.
• Hands-on experience scaling and deploying LLMs or other foundation models in real-world systems.
• Track record of mentoring other scientists and setting technical long-term vision.

Responsibilities

• Lead design, implementation, and deployment of research in reinforcement learning.
• Define scientific direction, mentor researchers, and drive innovations.
• Build and deploy reinforcement learning pipelines at scale.

Skills

Deep reinforcement learning

Programming

Leadership

Communication skills

Education

PhD in Computer Science or related field

Tools

Large compute clusters

Job description

Meet DeepL

DeepL is a global communications platform powered by Language AI. Since 2017, we’ve been on a mission to break down language barriers. Our human‑sounding translations and intelligent writing suggestions are designed with enterprise security in mind. Today, they enable over 100,000 businesses to transform communications, reach new markets, and improve productivity. And, empower millions of individuals worldwide to make sense of the world and express their ideas.

Our goal is to become the global leader in Language AI, building products that drive better communication, foster connections, and make a real‑life impact. To achieve this, we need talented individuals like you to join our exciting journey. If you're ready to work with a dynamic team and build your career in the fast‑moving AI space, DeepL is your next destination.

What sets us apart

What sets us apart is our blend of modern technology, competitive benefits, and an open, welcoming work culture that enables our people to thrive. When we share what it's like to work at DeepL, the reactions are overwhelmingly positive. This may be because of our products that have helped countless people worldwide or our shared mission to improve communication for individuals and businesses, bringing cultures closer together. What we know for sure is this: being part of DeepL means joining a team dedicated to innovation and employee well‑being. Discover what our teams have to say about life at DeepL on LinkedIn, Instagram and our Blog.

Meet the team behind this journey: Foundation Model Task Adaptation

We are the team behind DeepL’s post‑training stack for large language models. We focus on developing algorithms and systems that align pre‑trained models with tasks and performance goals through techniques like reinforcement learning. As a research‑driven team, we stay up to date with current literature to integrate cutting‑edge ideas into our core stack. As part of this team, you will shape the future of how our models learn beyond pre‑training — enabling new capabilities, better controllability, and safer, more effective user experiences.

Your responsibilities

As a Senior Staff Research Scientist, you’ll lead the design, implementation, and deployment of cutting‑edge research in reinforcement learning and post‑training at scale. You will define DeepL’s scientific direction in this area, mentor researchers, and drive innovations that make it into production.

You will:

• Shape scientific strategy and vision for post‑training across DeepL, identifying high‑leverage directions, setting technical standards and leading research initiatives in a highly dynamic, fast‑paced environment
• Build and deploy state‑of‑the‑art reinforcement learning pipelines at scale
• Post‑train large (multi‑modal) models to align them with human intent and enable general capabilities such as reasoning, pushing the boundaries of model performance, safety, and efficiency
• Drive the entire lifecycle of research and production: from idea conception, theoretical modeling, prototyping, ablation studies, all the way to production deployment
• Work closely with cross‑functional leadership to shape the technical strategy and priorities of the foundational models research track
• Build and foster external collaborations with academic and industrial partners
• Set scientific and technical standards for experimentation, reproducibility, and model evaluation
• Collaborate deeply with Engineering, ML Platform, and HPC teams to deliver robust and reliable model updates to users
• Mentor and guide senior scientists, researchers, and engineers, fostering a culture of excellence, curiosity, and impact

Qualities we look for

We’re looking for a senior‑staff‑level scientist with a deep technical background, strong leadership skills, and a proven track record of driving research in reinforcement learning or large‑scale model alignment to production.

• PhD (or equivalent experience) in Computer Science, Machine Learning, Applied Mathematics, Physics or a related field
• 5+ years of experience in ML research, including several years leading high‑impact projects with responsibilities extending across different teams
• Strong expertise in deep reinforcement learning (RLHF/RLAIF/RLVR)
• Hands‑on experience scaling and deploying LLMs or other foundation models in real‑world systems
• Strong programming skills and experience working with large compute clusters and ML infrastructure
• Excellent communication skills — able to clearly explain complex topics to diverse audiences
• Track record of mentoring other scientists and setting technical long‑term vision

What we offer

• Diverse and internationally distributed team: joining our team means becoming part of a large, global community with people of more than 90 nationalities. We’re more than just colleagues; we’re a group of professionals with a shared mission to connect diverse cultures. Our global presence is growing – we’ve doubled in size nearly every year, with employees based in the UK, Germany, the Netherlands, Poland, the US, and Japan, and we continue to expand our network.
• Open communication, regular feedback: as a language‑focused company, we value the importance of clear, honest communication. We value smooth collaboration, direct and actionable feedback, and believe that leading with empathy and growth mindset makes us better together.
• Hybrid work, flexible hours: we offer a hybrid work schedule, with team members coming into the office three times a week. This allows you to engage directly with your team and experience the unique energy of our workspace, while still enjoying the flexibility and comfort of working from home. With flexible working hours and trust in your productivity, we are in sync with your team’s general locations and time zones to foster effective and seamless collaboration.
• Monthly full‑day hacking sessions: every month, we have Hack Fridays, where you can spend your time diving into a project you’re passionate about and get the opportunity to work with other teams – we value your initiatives, impact, and creativity.
• 30 days of annual leave: we value your peace of mind. With 30 days off (excluding public holidays) and access to mental health resources, we make sure you’re as strong mentally as you are professionally.
• Competitive benefits: just as our team spans the globe, so does our benefits package. We’ve crafted it to reflect the diversity of our team and tailored it to align with your unique location, to ensure you feel supported every step of the way.

If this role and our mission resonate with you, but you're hesitant because you don't check all the boxes, don't let that hold you back. At DeepL, it's all about the value you bring and the growth we can foster together. Go ahead, apply—let's discover your potential together. We can't wait to meet you!

We are an equal opportunity employer

You are welcome at DeepL for who you are—we appreciate authenticity here. Our product is for everyone, and so is our workplace. The more voices we have represented and amplified in our business, the more we will all succeed, contribute, and think forward! So bring us your personal experience, your perspectives, and your background. It’s in our diversity that we will find the power to break down language barriers in the world.