
DeepL · London
MEET DEEPL DeepL is a global AI product and research company focused on building secure, intelligent solutions to complex business problems. Over 200,000 busin...
DeepL is a global AI product and research company focused on building secure, intelligent solutions to complex business problems.
Over 200,000 business customers and millions of individuals across 228 global markets today trust DeepL's Language AI platform for
human-like translation, improved writing and real-time voice translation.
Founded in 2017 by CEO Jaroslaw “Jarek” Kutylowski, DeepL now has around 1,000 passionate employees and is supported by
world-renowned investors including Benchmark, IVP, and Index Ventures.
Our goal is to become the global leader in trusted, intelligent AI technology, building products that drive better communication,
foster connections, and create a meaningful impact. To achieve this, we need talented people like you to join our journey. If
you’re ready to shape the future of AI and grow your career in a fast-moving, purpose-driven environment, DeepL is your next
destination.
What sets us apart is our blend of cutting-edge AI technology, meaningful work, and a culture where people truly thrive. We’re a
team of innovators, researchers, and creators driven by a shared purpose to unlock human potential by making work simpler,
smarter, and more connected.
When we share what it’s like to work at DeepL, the reactions are overwhelmingly positive. This might be because of our technology
that helps millions of people and businesses communicate and work better every day, or because of the trust, curiosity, and care
that shape our culture.
What we know for sure is this: being part of DeepL means joining a team dedicated to innovation, growth, and well-being. Discover
more about life at DeepL onLinkedIn,Instagram, and our Blog.
Our Language AI teams form the foundation of DeepL's success. We are a dedicated group of researchers who collaborate closely with
engineers, product managers, and designers. Our mission is to build the world's leading language AI system to deliver perfect
translations for the most demanding use cases. To that end, we take responsibility for the entire life cycle of the machine
learning models that power our language AI products. This includes data, training, quality assurance, and operational aspects. In
our highly collaborative teams, each person has the scope to drive impact across the company.
We are looking for a Senior Research Scientist to lead fine-tuning, post-training, model-steerability, and reinforcement learning
for the next generation of DeepL's LLM-based translation models. This is a high-impact, hands-on role for a researcher who can own
a major research direction, prototype rapidly, run large-scale experiments, and drive breakthroughs all the way into production.
Your central focus is how we blend data and shape model behaviour after pre-training. You will fuse high-value human expert data
with synthetic data, and you will lead the effort to make our translation models steerable, following custom user instructions,
rules, and context. You will work with model architectures at the scale of hundreds of billions of parameters.
distillation, preference optimization, and reinforcement learning tuned to translation quality.
mitigate reward hacking and quality-estimation failure modes.
deployment, working closely with engineering to ship into real-time systems at scale.
given behavior, drawing from instruction tuning, latent space methods, steering vectors, and/or constrained encoding and
decoding methods.
reinforcement learning (RLHF/RLAIF, PPO/GSPO, and reward modeling).
and filtering, and reasoning about data mixtures and ablations.
and human-in-the-loop evaluation.
production while staying grounded in product impact and real-world quality.
research team.
research with product and engineering priorities.
DeepSpeed, or Megatron-style frameworks) and efficient training techniques.
capabilities.
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 our employees based in the UK,
Germany, the Netherlands, Poland, the US, and Japan, and we continue to expand our network.
value smooth collaboration, direct and actionable feedback, and believe that leading with empathy and growth mindset makes us
better together.
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.
employee receives Virtual Shares, linking your contribution directly to DeepL’s growth and rewarding you with a stake in our
future.
gatherings, to new-joiner onboardings, to company-wide events that bring us all together–literally.
you're passionate about and get the opportunity to work with other teams–we value your initiatives, impact, and creativity.
resources, we make sure you're as strong mentally as you are professionally.
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!
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.
MEET DEEPL DeepL is a global AI product and research company focused on building secure, intelligent solutions to complex business problems. Over 200,000 business customers and millions of individuals across 228 global markets today trust DeepL's Language AI platform for human-like translation, improved writing and real-time voice translation. Founded in 2017 by CEO Jaroslaw “Jarek” Kutylowski, DeepL now has around 1,000 passionate employees and is supported by world-renowned investors including Benchmark, IVP, and Index Ventures. Our goal is to become the global leader in trusted, intelligent AI technology, building products that drive better communication, foster connections, and create a meaningful impact. To achieve this, we need talented people like you to join our journey. If you’re ready to shape the future of AI and grow your career in a fast-moving, purpose-driven environment, DeepL is your next destination. WHAT SETS US APART What sets us apart is our blend of cutting-edge AI technology, meaningful work, and a culture where people truly thrive. We’re a team of innovators, researchers, and creators driven by a shared purpose to unlock human potential by making work simpler, smarter, and more connected. When we share what it’s like to work at DeepL, the reactions are overwhelmingly positive. This might be because of our technology that helps millions of people and businesses communicate and work better every day, or because of the trust, curiosity, and care that shape our culture. What we know for sure is this: being part of DeepL means joining a team dedicated to innovation, growth, and well-being. Discover more about life at DeepL onLinkedIn,Instagram, and our Blog. MEET THE TEAM BEHIND THIS JOURNEY Our Language AI teams form the foundation of DeepL's success. We are a dedicated group of researchers who collaborate closely with engineers, product managers, and designers. Our mission is to build the world's leading language AI system to deliver perfect translations for the most demanding use cases. To that end, we take responsibility for the entire life cycle of the machine learning models that power our language AI products. This includes data, training, quality assurance, and operational aspects. In our highly collaborative teams, each person has the scope to drive impact across the company. YOUR RESPONSIBILITIES We are looking for a Senior Research Scientist to own the foundational modelling decisions behind the next generation of our most capable translation models. This is a high-impact, hands-on role for a researcher who can prototype rapidly, run large-scale experiments, and drive modelling choices all the way into production. In this competitive and highly dynamic field, you will decide which foundation models we build on, which architectures we adopt as we scale, and how we adapt a strong base model into a highly capable translation system working side by side with our post-training, RL, and instruction-following experts. YOU WILL: * Drive the selection and evaluation of open foundation / open-weight models as the basis for our next-generation translation systems. * Lead model selection and general architecture decisions for scaling to hundreds of billions of parameters, including Mixture-of-Experts and other sparse or efficient designs. * Design multi-capability adaptation strategies using LoRA, PEFT, and related methods. * Own the modelling lifecycle for your work: prototyping, ablations, scaling experiments, evaluation, and delivery into production, with rigorous and reproducible evaluation. * Partner closely with post-training, RL/RLHF, and instruction-following specialists to integrate alignment and capability work into the base model. * Stay ahead of the open-model and scaling literature, and bring well-founded recommendations back to the team. QUALITIES WE LOOK FOR * Strong hands-on experience adapting and scaling large language models via fine-tuning, instruction-tuning, or post-training of multi-billion-parameter models beyond black-box use. * Sound judgment about architecture trade-offs at scale (e.g. dense vs. MoE) and about which open-weight foundation models to build on. * Working knowledge of parameter-efficient and multi-capability adaptation (LoRA/PEFT and variants). * A hands-on builder who enjoys training models, running experiments, and debugging pipelines, and who can carry research results through to production with engineering. * Strong coding and experimentation skills (Python, PyTorch/JAX/Tensorflow). * Ability to communicate clearly, collaborate across teams, and align research work with product and engineering priorities. NICE TO HAVE * Experience quantifying uncertainty in large models — calibration and confidence estimation via Bayesian methods, ensembling, steering, or prompt-based approaches. * Experience with machine translation, multilingual NLP, or document-/layout-aware modelling experience. * Familiarity with MoE-specific training and adaptation (e.g. expert routing, Mixture-of-LoRA-Experts) and large-scale data-mixture design. 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 our 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 twice 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. * Virtual Shares - An ownership mindset in every role. We believe everyone should share in our success, and that’s why every employee receives Virtual Shares, linking your contribution directly to DeepL’s growth and rewarding you with a stake in our future. * Regular in-person team events: we bond over vibrant events that are as unique as our team, from local team and business unit gatherings, to new-joiner onboardings, to company-wide events that bring us all together–literally. * 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.
WHY FACULTY? We established Faculty in 2014 because we thought that AI would be the most important technology of our time. Since then, we’ve worked with over 350 global customers to transform their performance through human-centric AI. You can read about our real-world impact here. We don’t chase hype cycles. We innovate, build and deploy responsible AI which moves the needle - and we know a thing or two about doing it well. We bring an unparalleled depth of technical, product and delivery expertise to our clients who span government, finance, retail, energy, life sciences and defence. Our business, and reputation, is growing fast and we’re always on the lookout for individuals who share our intellectual curiosity and desire to build a positive legacy through technology. AI is an epoch-defining technology, join a company where you’ll be empowered to envision its most powerful applications, and to make them happen. ABOUT THE TEAM We are the central research and development team driving Faculty's broader AI safety charter. We pioneer fundamental and applied technical AI safety research, producing rigorous scientific outputs—including publications, tooling, and technical reports—that advance the theory and practice of AI safety and directly shape the work of frontier AI labs, government agencies, and national security institutes. Our research spans both black-box and white-box approaches to understanding and steering AI systems. We care deeply about interpretability, faithfulness, and principled mitigation strategies, with a particular focus on the mechanistic and behavioural study of transformer-based large language models and long-running agentic systems. We operate at the cutting edge of the field, with current research threads including: * System Understanding: Interpretability, steering vectors, and the science of evaluations. * Control & Alignment: Goal drift, machine unlearning, and uncertainty calibration. * Societal Safeguards: Misinformation mitigation and robust deployment boundaries. We collaborate closely with the Faculty's wider AI safety team, a group with a well-established track record in capability evaluations and red-teaming for misuse risk across CBRN, cybersecurity, and international security. That work has been conducted for several leading frontier model developers and national safety institutes, and has been featured in OpenAI's o1 system card and Meta Muse Spark’s Safety & Preparedness Report. ABOUT THE ROLE As a Senior Research Scientist at Faculty, you will join our high-impact R&D team to lead original technical research that advances our understanding of safe AI systems. Operating with high agency, you will balance scientific rigour with practical relevance to shape the future of safe AI deployment. Working closely with our broader AI safety practice, your scientific outputs—ranging from peer-reviewed publications to technical tooling—will directly inform frontier labs and government institutes, driving our entrepreneurial ambition to build a safer technological future. WHAT YOU'LL BE DOING: * Leading original technical research in AI safety, steering projects from initial research question to high-impact publication. * Shaping the research agenda by identifying high-impact projects that balance scientific rigour with real-world relevance. * Contributing thought leadership and deep technical expertise to support wider evaluation and red-teaming efforts. * Supporting our positioning as a global leader through active external engagement with frontier labs and government stakeholders. * Developing robust, reproducible research code and engineering infrastructure to accelerate our scientific discovery. * Collaborating with cross-functional safety teams to translate fundamental research into practical mitigation strategies. WHO WE'RE LOOKING FOR: * Strong track record in AI research, evidenced by publications or equivalent experience, alongside the ability to tackle open, unsolved problems. * Capability to own research end-to-end, moving independently from framing novel problems to generating high-quality research artifacts. * Passion for technical AI safety, whether developed in academia, industry labs, or evaluation roles. * Deep knowledge of language models and generative AI architectures, including white-box techniques beyond API-level access. * Strong foundation in machine learning fundamentals, particularly in robustness, explainability, or uncertainty estimation. * Proficiency with deep learning frameworks like PyTorch and the Python skills required to build robust research tooling. OUR RECRUITMENT ETHOS We aim to grow the best team - not the most similar one. We know that diversity of individuals fosters diversity of thought, and that strengthens our principle of seeking truth. And we know from experience that diverse teams deliver better work, relevant to the world in which we live. We’re united by a deep intellectual curiosity and desire to use our abilities for measurable positive impact. We strongly encourage applications from people of all backgrounds, ethnicities, genders, religions and sexual orientations. Some of our standout benefits: * Unlimited Annual Leave Policy * Private healthcare and dental * Enhanced parental leave * Family-Friendly Flexibility & Flexible working * Sanctus Coaching * Hybrid Working If you don’t feel you meet all the requirements, but are excited by the role and know you bring some key strengths, please don't hesitate in applying as you might be right for this role, or other roles. We are open to conversations about part-time hours.
WHY FACULTY? We established Faculty in 2014 because we thought that AI would be the most important technology of our time. Since then, we’ve worked with over 350 global customers to transform their performance through human-centric AI. You can read about our real-world impact here. We don’t chase hype cycles. We innovate, build and deploy responsible AI which moves the needle - and we know a thing or two about doing it well. We bring an unparalleled depth of technical, product and delivery expertise to our clients who span government, finance, retail, energy, life sciences and defence. Our business, and reputation, is growing fast and we’re always on the lookout for individuals who share our intellectual curiosity and desire to build a positive legacy through technology. AI is an epoch-defining technology, join a company where you’ll be empowered to envision its most powerful applications, and to make them happen. ABOUT THE TEAM We are the central research and development team within Faculty's broader AI safety charter. Our group focuses on fundamental and applied technical AI safety research, producing rigorous scientific outputs - publications, tooling, technical reports & evaluations - that advance the theory, practice and understanding of AI risks, and directly inform the work of frontier AI labs, government agencies, and national security institutes. Our research spans fundamental research using black-box and white-box approaches to understand and steer AI systems, to building and advancing safety evaluations which better understand and quantify risks in AI. We care deeply about mechanistic understanding and scientific rigour in measuring risks in AI systems. Current research threads include (but are not limited to) uncertainty calibration, goal drift, misinformation mitigation, steering vectors, robust safeguard measurement and the science of evaluations. We collaborate closely with the Faculty's wider AI safety team, a group with a well-established track record in capability evaluations and red-teaming for misuse risk across CBRN, cybersecurity, societal and psychosocial harms. That work has been conducted for several leading frontier model developers and national safety institutes, and has been featured in model cards and safety reports from Anthropic, GDM, Meta & OpenAI. ABOUT THE ROLE As a Senior Research Scientist at Faculty, you will lead the development of cutting-edge safety evaluations to quantify AI risks in critical domains like CBRN and Cyber. Joining our high-impact R&D team, you will drive original research that advances safety methodology while collaborating with delivery teams building evaluations and red-teaming for frontier labs. This is a high-agency opportunity to conduct technical AI safety research that produces scientific outputs shaping the future of safe real-world AI deployment. WHAT YOU'LL BE DOING * Leading the development of novel safety evaluations in high-impact domains such as CBRN and Cyber to quantify emerging risks. * Executing original technical research in AI safety evaluation methods, taking ideas from concept to publication. * Shaping the R&D agenda by identifying strategic opportunities to advance safety evaluation methodology across Faculty and the broader ecosystem. * Contributing thought leadership and deep technical expertise to client delivery projects, evaluation work, and red-teaming for frontier labs. * Representing Faculty’s scientific leadership through active external engagement with the global research community, frontier labs, and government stakeholders. WHO WE'RE LOOKING FOR * A track record of owning research end-to-end—from identifying novel problems to publication—driven by scientific curiosity and tenacity. * Hands-on experience designing and building AI evaluations or benchmarks, alongside a strong ability to reason about construct validity and mitigate confounds. * Expertise in red-teaming, adversarial testing, jailbreaking, indirect prompt injection, and assessing the robustness of model safeguards. * Strong foundational skills in experimental design, statistical analysis, and uncertainty quantification, including Bayesian methods. * Deep knowledge of language models, generative AI architectures, training methodologies, and safety mitigation techniques. * Solid Python proficiency combined with the engineering discipline required to build robust, reproducible research. NICE TO HAVES * Experience in threat and risk modelling. * Background or knowledge in high-risk domains such as CBRN or Cybersecurity. * A history of high-impact AI research, evidenced by top-tier publications or equivalent practical achievements. OUR RECRUITMENT ETHOS We aim to grow the best team - not the most similar one. We know that diversity of individuals fosters diversity of thought, and that strengthens our principle of seeking truth. And we know from experience that diverse teams deliver better work, relevant to the world in which we live. We’re united by a deep intellectual curiosity and desire to use our abilities for measurable positive impact. We strongly encourage applications from people of all backgrounds, ethnicities, genders, religions and sexual orientations. Some of our standout benefits: * Unlimited Annual Leave Policy * Private healthcare and dental * Enhanced parental leave * Family-Friendly Flexibility & Flexible working * Sanctus Coaching * Hybrid Working If you don’t feel you meet all the requirements, but are excited by the role and know you bring some key strengths, please don't hesitate in applying as you might be right for this role, or other roles. We are open to conversations about part-time hours.