Senior Full Stack Engineer (Must be based in UK)

Senior Full Stack Engineer (Must Be Based In UK)

London

PolyAI automates customer service through lifelike voice assistants that let customers lead a conversation. Our voice assistants make it possible for businesses to deliver outstanding customer service that rivals their human agents. Our customers, which include the world's leading logos, are expanding how they use our platform, driving automation of critical customer service operations and integrating PolyAI into their daily customer service workflows.

PolyAI just raised our Series D from leading investors, such as Nvidia and Khosla Ventures, bringing our total funding to $200m. We serve enterprises where customer conversation is a critical part of doing business, partnering with leading companies such as Fedex, Marriott Hotels and Unicredit. Our AI agents have proven themselves to deliver significant customer value, at some enterprises doing the work of 1000+ FTEs.

We're looking for a Senior Full Stack Engineer (with strong backend skills) to join our product engineering team at a moment of exponential growth for our company.

The Supervisor Suite team's mission is to build best-in-class conversational intelligence, LLM-powered evaluation and data tools for PolyAI's customer service agents. Our users are customer experience leaders, business analysts and contact center managers. We enable them to answer questions such as:

• How can we automate more of our business while increasing customer satisfaction?
• Did the voice agent respect our policies and procedures?
• What do our customers think about our offering?

You might work on:

• LLM judges that evaluate our customer service AI agents for quality, safety and reliability at scale
• Smart Analyst, our flagship AI research agent for conversational data leveraging the latest agent harness and context engineering practices, to maximize insight per token
• Data pipelines that process millions of conversations daily and are at the foundation of PolyAI's architecture
• Real-time dashboards and alerting systems providing observability of our AI agents

You'll own features end-to-end, from collaborating on product direction and system design through to implementation and seeing real customers light up when they use what you've built. And because we're scaling fast, you'll get to experience what few engineers do: evolving your products and architecture in real-time as data volumes grow and customer needs expand.

If you love building products that blend great UX with complex backend challenges, thrive in collaborative environments where engineers shape product decisions, and want to work on AI applications that are actually solving real business problems today, we'd love for you to join us!

What You Will Do

• Full-Stack Development: Design and implement features end-to-end, using Python for backend services and React (Next.js preferred) for frontend interfaces.
• Create Intuitive Interfaces: Develop user-friendly UIs that simplify and visualise complex AI concepts.
• Champion Best Practices: Lead the team in adopting coding standards and best practices, ensuring a clean, maintainable, and scalable codebase.
• Collaborate: Work closely with cross-functional teams to design, develop, and deliver features that align with the platform's vision.
• Mentor and Guide: Provide technical leadership and guidance to junior engineers, fostering a collaborative and growth-oriented environment.
• Optimise Performance: Improve backend workflows, streamline processes, and enhance overall system efficiency.

What We Are Looking For

• Problem Solving: We are looking for people who enjoy diving into complex problems and possess high intellectual agility. Our team tackles novel challenges at the forefront of building AI agents, and is responsible for maintaining large-scale and critical services.
• 4+ YOE in software engineering with a track-record of delivering complex features end-to-end in a high-ownership environment.
• Proven Expertise in Python and SQL: Extensive experience building backend systems, with a strong understanding of REST APIs. Experience with designing data schemas, building and maintaining data pipelines/ETLs (familiarity with event-driven processing is a plus).
• Frontend Confidence: Strong experience with React and JavaScript (TypeScript preferred); experience with Tailwind.
• Testing Advocate: Experience writing and maintaining unit tests in Python and JavaScript (Jest).
• Collaborative Development: Proficiency with Git and experience working in team-based development workflows.

Additional Skills (Desirable):

• Knowledge of Golang.
• Experience with Next.js.
• Experience building production-grade systems incorporating LLMs

We currently have multiple engineering roles open across different teams. Please apply to the one role that feels like the best match for your skills and experience. Our Talent team will review your application against all open positions. If we believe you may be a stronger fit for another role or team, we'll ensure your application is considered there as well.

Benefits

Participation in the company's employee share options plan

Tenure-Based PTO: You will receive 25 holidays when you join and will gain an additional 1 day after 2 years of service, then 1 day each year until capped at 32 holidays

Flexible working from home policy

Work from outside of the UK for up to 6 months each year

TELUS Health EAP 24/7 - offers you and your chosen family confidential, judgment-free support for any work, health, or life challenge

Enhanced parental leave

Bike2Work scheme

Annual learning and development allowance

We're all about making WFH work for you - that's why we offer a one-off WFH allowance when you join. Offering perks like noise-cancelling headphones or a comfortable desk chair to boost your comfort and focus!

Company-funded fertility and family-forming programmes

Menopause care programme with Maven

Private healthcare and dental cover, discounts on gym members and relaxation apps, and access to a range of mental health programs

Sabbatical Program: 5-week paid sabbatical available after 5 years of employment

At PolyAI, we take great pride in our values - they guide everything we do. We believe that a strong culture leads to meaningful work and lasting impact.

Our core values are:

Only the best We expect the best from our people, we hire people that expect the best from themselves, and we nurture this drive for excellence.

Ownership We care deeply about what we do. We take ownership of our initiatives, decisions and outcomes.

Relentlessly improve We demand more from ourselves and are always evolving. Continuous, obsessive improvement is the only way we will transform the world of conversational AI.

Bias for action Our world moves quickly and so do we. We take calculated risks and we deliver impact fast.

Disagree and commit We are all working toward the same goal. If we don't agree with something, we work hard to understand it and when a decision is made, we accept it and give it our all.

Build for people We want the world to enjoy the experiences they have with us. We are building for a future that prefers automation.

PolyAI is proud to be an equal-opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. All employment decisions at PolyAI will be based on the business needs without attention to ethnicity, religion, sexual orientation, gender identity, family or parental status, national origin, neurodiversity status or disability status.