Research Engineer, Production Model Post-Training London

Anthropic
London

About Anthropic

Anthropics mission is to create reliable interpretable and steerable AI systems. We want AI to be safe and beneficial for our users and for society as a whole. Our team is a quickly growing group of committed researchers engineers policy experts and business leaders working together to build beneficial AI systems.

About the role

Anthropics production models undergo sophisticated post-training processes to enhance their capabilities alignment and safety. As a Research Engineer on our Post-Training team youll train our base models through the complete post-training stack to deliver the production Claude models that users interact with.

Youll work at the intersection of cutting-edge research and production engineering implementing scaling and improving post-training techniques like Constitutional AI RLHF and other alignment methodologies. Your work will directly impact the quality safety and capabilities of our production models.

Note: For this role we conduct all interviews in Python. This role may require responding to incidents on short-notice including on weekends.

Responsibilities:

  • Implement and optimize post-training techniques at scale on frontier models

  • Conduct research to develop and optimize post-training recipes that directly improve production model quality

  • Design build and run robust efficient pipelines for model fine-tuning and evaluation

  • Develop tools to measure and improve model performance across various dimensions

  • Collaborate with research teams to translate emerging techniques into production-ready implementations

  • Debug complex issues in training pipelines and model behavior

  • Help establish best practices for reliable reproducible model post-training

You may be a good fit if you:

  • Thrive in controlled chaos and are energised rather than overwhelmed when juggling multiple urgent priorities

  • Adapt quickly to changing priorities

  • Maintain clarity when debugging complex time-sensitive issues

  • Have strong software engineering skills with experience building complex ML systems

  • Are comfortable working with large-scale distributed systems and high-performance computing

  • Have experience with training fine-tuning or evaluating large language models

  • Can balance research exploration with engineering rigor and operational reliability

  • Are adept at analyzing and debugging model training processes

  • Enjoy collaborating across research and engineering disciplines

  • Can navigate ambiguity and make progress in fast-moving research environments

Strong candidates may also:

  • Have experience with LLMs

  • Have a keen interest in AI safety and responsible deployment

We welcome candidates at various experience levels with a preference for senior engineers who have hands-on experience with frontier AI systems. However proficiency in Python deep learning frameworks and distributed computing is required for this role.

The annual compensation range for this role is listed below.

For sales roles the range provided is the roles On Target Earnings (OTE) range meaning that the range includes both the sales commissions/sales bonuses target and annual base salary for the role.

Annual Salary:

260000 - 370000 GBP

Logistics

Education requirements: We require at least a Bachelors degree in a related field or equivalent experience.

Location-based hybrid policy: Currently we expect all staff to be in one of our offices at least 25% of the time. However some roles may require more time in our offices.

Visa sponsorship: We do sponsor visas! However we arent able to successfully sponsor visas for every role and every candidate. But if we make you an offer we will make every reasonable effort to get you a visa and we retain an immigration lawyer to help with this.

We encourage you to apply even if you do not believe you meet every single qualification. Not all strong candidates will meet every single qualification as listed. Research shows that people who identify as being from underrepresented groups are more prone to experiencing imposter syndrome and doubting the strength of their candidacy so we urge you not to exclude yourself prematurely and to submit an application if youre interested in this work. We think AI systems like the ones were building have enormous social and ethical implications. We think this makes representation even more important and we strive to include a range of diverse perspectives on our team.

Your safety matters to us. To protect yourself from potential scams remember that Anthropic recruiters only contact you some cases we may partner with vetted recruiting agencies who will identify themselves as working on behalf of Anthropic. Be cautious of emails from other domains. Legitimate Anthropic recruiters will never ask for money fees or banking information before your first day. If youre ever unsure about a communication dont click any linksvisit

How were different

We believe that the highest-impact AI research will be big science. At Anthropic we work as a single cohesive team on just a few large-scale research efforts. And we value impact advancing our long-term goals of steerable trustworthy AI rather than work on smaller and more specific puzzles. We view AI research as an empirical science which has as much in common with physics and biology as with traditional efforts in computer science. Were an extremely collaborative group and we host frequent research discussions to ensure that we are pursuing the highest-impact work at any given time. As such we greatly value communication skills.

The easiest way to understand our research directions is to read our recent research. This research continues many of the directions our team worked on prior to Anthropic including: GPT-3 Circuit-Based Interpretability Multimodal Neurons Scaling Laws AI & Compute Concrete Problems in AI Safety and Learning from Human Preferences.

Come work with us!

Anthropic is a public benefit corporation headquartered in San Francisco. We offer competitive compensation and benefits optional equity donation matching generous vacation and parental leave flexible working hours and a lovely office space in which to collaborate with colleagues. Guidance on Candidates AI Usage: Learn about our policyfor using AI in our application process

Required Experience:

IC

Posted 2026-01-18

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