AI Applied Scientist

We exist to make migration easy.

A systemic problem of this magnitude requires a team of curious thinkers who relentlessly pursue solutions. Those who constantly challenge the why, dismantle assumptions, and always take action to build a better way.

A Marshmallow career is built on a cycle of continuous growth, with learning at its core. You will be challenged to raise the bar on your capabilities and supported with the right tools and guidance to do so. This ensures you can deliver impactful work and drive change.

If life at Marshmallow sounds like it could be for you, explore our Culture Handbook to find out more.

Move our mission, and your career, forward.

Data holds the secret code that unlocks the path ahead in our mission. That’s why data teams at Marshmallow are crucial in helping us to create technological solutions that make migration easy for hundreds of millions of global relocators every year.

Insightful. Strategic. Rigorous. A true team-player. Always ready to improve. We look for talent who’ll use their technical brilliance to build credibility across the business and make real commercial and world impact with every choice.

That’s why we provide a supportive environment full of trust and autonomy. So you can take ownership of high-leverage work, in a top functioning team that’s always moving forward.

Our AI & Automation team is at the forefront of transforming how we engage with our customers by building intelligent, agentic AI solutions that enhance customer interactions and operational efficiency. This team plays a critical role within the Retention tribe, focusing on delivering cutting-edge conversational AI technologies that support complex, high-stakes customer journeys such as policy renewals and retention negotiations.

The team works closely with cross-functional partners across Product, Operations, Finance, and senior leadership to ensure AI-driven solutions are robust, compliant, and aligned with Marshmallow’s strategic goals.

Joining this team means being part of a fast-moving, innovative environment where curiosity, collaboration, and continuous learning are essential. You’ll help shape the future of AI-powered customer experiences in a regulated industry, tackling unique challenges that require both technical expertise and strong communication skills to bridge the gap between technology and business.

As an AI Applied Scientist at Marshmallow, you will lead the development and refinement of customer-facing AI agent solutions, focusing on implementing and enhancing conversational AI through our Sierra platform. Your role bridges data science and AI application, driving the evolution of high-performing, robust systems that deliver complex, real-world interactions such as retention negotiations and personalised customer engagement. You will collaborate across teams to translate cutting-edge AI capabilities into practical, regulated solutions that improve customer experience and operational efficiency, while helping to shape the future of AI-driven financial products at Marshmallow.

• Lead the design, development, and implementation of customer-facing AI agent solutions.

• Develop and refine conversational AI models to achieve human-equivalent performance in complex customer interactions.

• Establish and maintain robust evaluation frameworks and monitoring systems to ensure AI quality, compliance, and regulatory standards.

• Drive experimentation and iterative improvement cycles to enhance AI agent capabilities and customer experience.

• Own the end-to-end lifecycle of AI agent deployments, including prompt design, context management, and troubleshooting to optimise conversational flow.

• Collaborate closely with cross-functional teams, acting as a technical bridge, communicating complex AI concepts clearly to both technical teams and senior leadership.

• You are deeply curious and passionate about the fast-evolving field of AI, especially in customer-facing generative AI and conversational agents.

• You thrive in a dynamic, exploratory environment and are motivated by solving complex, high-stakes problems that have real-world impact.

• You communicate complex technical concepts clearly and effectively to both technical and non-technical stakeholders, bridging gaps in understanding.

• You take ownership and pride in building robust, high-performing AI systems that deliver measurable value and improve customer experiences.

• You are comfortable navigating ambiguity and can design thoughtful experimentation frameworks to iterate and improve AI-driven customer journeys.

• You are enthusiastic about being a key voice in shaping the future of AI applications within the company and beyond, helping to build internal knowledge and capabilities.

• Proven experience working with customer-facing generative AI or conversational AI solutions.

• Strong background in data science with hands-on experience deploying and evaluating machine learning or AI models, particularly large language models (LLMs).

• Deep understanding of prompt engineering, LLM evaluation, and agentic AI systems, with the ability to design and optimize conversational flows

• Experience working with or integrating third-party AI platforms (e.g., Sierra) and collaborating with external technology partners.

• Solid SQL skills for data querying and analysis to support model evaluation and experimentation frameworks.

• Excellent communication skills with the ability to translate complex technical concepts to non-technical stakeholders and senior leadership.

• Flexi-office working – Spend 2-3 days a week with your team in our new collaborative London office. The rest is up to you! 🏠

• Competitive bonus scheme - designed to reward and recognise high performance 🌟

• Flexible benefits budget - £50 per month to spend on a Ben Mastercard, meaning you get your own benefits budget to spend on things you want. Whether that’s subscriptions, night classes (puppy yoga, anyone?), the big shop or a forest of houseplants. Pretty much anything goes 💰

• Sabbatical Leave - Get a 4-week fully paid sabbatical after being with us for 4 years 🏝️

• Work From Anywhere - 4 weeks work from anywhere to use, with no need to come to the office 🛫

• Mental wellbeing support – Access therapy and mental health sessions through Oliva 💚

• Learning and development – Personal budgets for books and training courses to help you grow in your role. Plus 2 days a year - on us! - to further your skillset 🤓

• Private health care - Enjoy all the benefits Vitality has to offer, including reduced gym memberships and discounts on smartwatches 🏥

• Medical cash plan - To help you with the costs of dental, optical and physio (plus more!)

• Tech scheme - Get the latest tech for less 🖥

Plus all the rest; 33 days holiday, pension, cycle to work scheme, monthly team socials and company-wide socials every month!

Our process

We break it up into a few stages:

• Initial call with our Talent Acquisition Partner - 30 mins

• A past experience interview where you will discuss your journey so far and ways of working with Hannah, our hiring manager - 60 mins

• A technical interview with a couple of the team - 60 mins

• A culture interview with a bar raiser to see if your work style fits our processes and values (and vice versa!) - 60 mins

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At Marshmallow, we want to hire people from all walks of life with the passion and skills needed to help us achieve our company mission. To do that, we're committed to hiring without judgement, prejudice or bias.

We encourage everyone to apply for our open roles. Gender identity, race, ethnicity, sexual orientation, age or background does not affect how we process job applications.

We're working hard to build an inclusive culture that empowers our people to do their best work, have fun and feel that they belong.

We take privacy seriously here at Marshmallow. Our Recruitment privacy notice explains how we process and handle your personal data. To find out more please view it here.