Senior Full Stack Engineer (Must be based in UK) in 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.

Responsibilities:

• Contributing to our user-facing platform for building and configuring voice assistants
• Contributing to the implementation of our multi-tenant infrastructure, across multiple cloud vendors ensuring long-term scalability and maintainability
• Taking a major role in our software development, through writing code, tests, as well as contributing to design ideas, documents and performing code reviews
• Working independently on the technical design and implementation of full stack features for our agent studio platform, from UI through backend to data pipelines

Requirements:

• 3+ years as a professional Software Engineer, with significant experience delivering both backend and frontend features in production
• Proficiency in Python or Go, Typescript and React all a must
• Hands-on experience in designing, deploying, and maintaining RESTful APIs
• Experience with one or more cloud services: AWS, GCP, Azure
• Understanding of algorithms, data structures, system design and complexity analysis

We're looking for talented Senior Full Stack Software Engineers to join one of our three high impact teams: Runtime, Data, and Product Engineering. All three teams work closely together, share high engineering standards, and solve challenging technical problems at scale, but each has its own mission and area of focus.

Runtime: own the global infrastructure that powers real-time voice interactions. In this role, you'll work at the core of the agentic process - streaming audio, transcribing speech, using LLMs and acting on their output, and synthesising natural voice. You'll design and optimise systems across VoIP, WebRTC to deliver low-latency, secure, and reliable conversations. Your work directly shapes the user experience of every call, driving down response times, improving comprehension, and ensuring we meet strict SLAs for performance and security.

Data: play a key role in delivering the next generation of our no-code agent studio platform. You'll be leading the design and development of features that power insight generation, reporting, and the data-driven backbone of our no-code platform for building voice assistants.

Product Engineering: help shape our cutting-edge low-code platform. This role offers the opportunity to work end-to-end, from design to implementation, on creating features which enable a simple user experience for interacting with complex AI systems.

You'll go through a centralized hiring process that lets us get to know your skills and preferences, while you explore which team best aligns with your interests and expertise. At the end, we'll match you with the team where you can have the most impact.

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. 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 and culture:

• Participation in the company's employee share options plan
• Flexible working from home policy
• Work from outside of the UK for up to 6 months each year
• TELUS Health EAP 24/7 - confidential support for work, health, or life challenges
• Annual learning and development allowance
• One-off WFH allowance to improve comfort and focus
• Company-funded fertility and family-forming programmes
• Private healthcare and dental cover, gym discounts, and access to mental health programs

At PolyAI, we take great pride in our values — they guide everything we do. Our core values are:

• Only the best: We hire people who strive for excellence and push for the best outcomes.
• Ownership: We care deeply about what we do and take responsibility for initiatives and outcomes.
• Relentlessly improve: We continuously evolve to transform the world of conversational AI.
• Bias for action: We move quickly, take calculated risks, and deliver impact.
• Disagree and commit: We work to understand decisions and commit fully once they are made.
• Build for people: We build experiences that people enjoy and that enable automation.
• Equal opportunity: PolyAI is proud to be an equal-opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. Employment decisions are based on business needs without regard to ethnicity, religion, sexual orientation, gender identity, family or parental status, national origin, neurodiversity status or disability status.

Please note: This description excludes time-sensitive application forms and notices unrelated to the role.