Location
London, United Kingdom - Five days per week in the Old Street office.

Hours
Full-time, office-centric startup culture with a high-intensity work environment.

Salary
Competitive salary commensurate with experience.

About the Role
This is a staff-level product engineering role at a YC-backed, Series A AI company building autonomous voice agents for trades and field-services businesses. As one of the final founding engineering hires, you will shape both the technical foundations and the way the company works directly with customers. The role combines hands-on full-stack development, applied AI, infrastructure, integrations, and technical leadership in a fast-moving early-stage environment. You will build and ship core product features across Python, TypeScript, cloud infrastructure, event-driven systems, and third-party integrations. You will own customer problems from discovery and scoping through implementation and measurable outcomes, build and improve AI voice-agent workflows that interact reliably with real-world service operations, and decide when a fast MVP is appropriate versus when scalable, reliable foundations are needed. Additionally, you will raise engineering standards for testing, documentation, reliability, security, and operational quality while helping a small engineering team make sound architecture decisions and continuing to write production code.

Experience
- 5 to 10 years of full-stack software engineering experience with a backend emphasis.
- Meaningful experience building and shipping AI products end to end, especially agentic systems.
- Strong production experience with Python or TypeScript.
- Deep experience with asynchronous Python, including coroutines, HTTP clients, asynchronous model APIs, and robust error handling.
- Early-stage startup experience, ideally at Series A or earlier.
- Experience with Kubernetes, serverless systems, distributed infrastructure, or event-driven architecture.
- Ability to scope and deliver technical solutions directly with customers and non-technical stakeholders.

About you
- Strong technical leadership skills with a hands-on approach.
- Comfortable working in a fast-paced, early-stage startup environment.
- Customer-focused mindset with the ability to translate customer needs into technical solutions.
- Collaborative team player who can help raise engineering standards across the team.

Qualifications
- A computer science degree or equivalent technical foundation.

Bonus points
- Experience with voice AI, speech-to-text, text-to-speech, or telephony platforms.
- Experience building CRM or other complex third-party integrations.
- Previous founder experience or a strong customer-facing engineering background.
- Experience in fintech, trades software, or operationally complex vertical software.