As an AI Engineer, you will join a high-growth startup building the future of agentic integrations. Working directly with the CTO, you will develop end-to-end AI features, including tool-calling for agents and specialized LLMs. You will bridge the gap between AI research and production-grade software to enable one-click integrations for SaaS platforms.
Back to all jobs
Learn about Jack
AI Engineer at StackOne
Join one of Europe’s fastest-growing startups as an AI Engineer and build the future of agentic integrations. Backed by $24M from GV and Workday Ventures, this role places you at the center of a specialized AI R&D lab training LLMs for high-precision tool calling. You'll work alongside ex-Google and Microsoft veterans to ship production-grade AI features and open-source packages that enable agents to integrate with any tool in one click. With meaningful equity, private health, and a high-performance culture, this is a rare opportunity to shape the infrastructure of the agentic web.
About this role
Role overview
About the company
StackOne
SoftwareCanterbury, United KingdomSeries A (VC-backed)
StackOne is the AI Integration Gateway for SaaS products and AI Agents. With operations in the UK and US, the company enables builders of SaaS platforms and AI Agents to orchestrate hundreds of scalable, accurate, and enterprise-grade integrations. Their platform combines 25,000 pre-mapped actions on 200 connectors, an AI-powered integration development toolkit, plus security by design: a real-time architecture, managed authentication and permissions, and end-to-end observability. The company was founded by a team of former Google, Oracle, JP Morgan, Coinbase, and Microsoft employees with a mission to build the most advanced integration infrastructure for generative AI applications. StackOne has experienced rapid growth, serving enterprise clients globally, and is backed by notable investors, including GV (Google Ventures), Workday Ventures, and Episode 1.
Backed by GV (Google Ventures), Workday Ventures, XTX Ventures, Episode 1 Ventures, Playfair Capital, Founders of GitHub, Founders of Onfido, Founders of Hofy, Angel investors from OpenAI, Angel investors from Google DeepMind, Angel investors from Microsoft, Angel investors from MuleSoft.
What you'll do
What you will do
- Design, build, and ship full-stack AI features across backend, frontend, and infrastructure using TypeScript, Python, and AWS/Cloudflare.
- Build and maintain critical AI infrastructure, including inference pipelines, retrieval systems, and Model Context Protocol (MCP) implementations.
- Collaborate with AI researchers to deliver production-grade orchestration systems and publish internal or open-source SDKs and CLIs.
Who you are
Who this is a fit for
- Professional experience building and shipping production-grade applications using LLMs such as GPT or Anthropic models.
- Strong engineering background in TypeScript or Python with a track record of developing scalable systems on AWS, GCP, or Cloudflare.
- Proactive builder with a bias toward action and curiosity for pushing the boundaries of agent frameworks and AI-powered development.
Why this role
Why this role is remarkable
- Join a veteran team of ex-Google, Microsoft, and Oracle employees at one of Europe’s fastest-growing AI startups backed by top-tier VCs like GV (Google Ventures).
- Impact the cutting edge of AI R&D by helping build a specialized lab dedicated to training LLMs for high-precision, safety-critical agentic tool calling.
- Benefit from a high-growth environment with meaningful EMI share options, private health insurance, and a generous budget for your home office and daily lunch.
Jack & Jill
How Jack & Jill work together
I get to know what you’re great at, then find roles you’d never find yourself.Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.
I recruit from Jack’s network and make the intro when I spot a great match.And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.
Meet Jack
Jack gets to know what you're great at and what you want next, then searches 15 million jobs daily and helps you discover roles at companies like this.
How does this work?
Jack’s an AI agent for job searching and career coaching. He works for you.
Jill is the AI recruiter working for the company. She recruits from Jack’s network.
If it’s a match and the company wants to meet you, they’ll make the intro. In the meantime, if you’d like, Jack will send you excellent alternatives.