As an AI Engineer at StackOne, you will build the future of agentic integrations by delivering end-to-end AI products. Reporting to the CTO, you’ll work with AI researchers to develop specialized LLMs for tool-calling, ensuring precision and reliability in agentic execution while maintaining high-performance inference pipelines and retrieval systems.
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AI Engineer at StackOne
Join StackOne, the $24M GV-backed startup building the definitive AI Integration Gateway for SaaS products and AI Agents. As an AI Engineer in London, you’ll work directly with the CTO to push the boundaries of tool-calling and agentic execution. You will build production-grade inference pipelines, develop specialized LLMs, and help users integrate any agent with any tool in a single click. With a team of ex-Google and Microsoft veterans, meaningful EMI share options, and a mission to orchestrate the future of the agentic web, this is a unique chance to shape the next generation of AI-native software integrations.
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Location
London, United Kingdom
Compensation
Not Disclosed
Company
StackOne
Role overview
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 will do
- Design and deploy full-stack features including inference pipelines, embeddings, and retrieval systems across AWS and Cloudflare.
- Implement cutting-edge tool-calling and Model Context Protocol (MCP) patterns to enable one-click agent integrations with any tool.
- Develop and maintain high-quality open-source and internal TypeScript and Python packages to accelerate the developer ecosystem.
Who this is a fit for
- Professional experience shipping production-grade applications using Generative AI and LLMs like GPT or Anthropic.
- Expert proficiency in TypeScript and Python with a proven track record of building scalable systems on AWS, GCP, or Cloudflare.
- Strong background in full-stack engineering with experience publishing SDKs, CLIs, or complex packages in a fast-paced environment.
Why this role is remarkable
- Work at the frontier of AI R&D, building specialized LLMs designed for tool-calling and agentic execution rather than just general-purpose applications.
- Join a high-growth startup backed by elite investors like GV and Workday Ventures, scaling a platform that already powers thousands of integrations.
- Collaborate with a world-class veteran engineering team from industry leaders like Google, Microsoft, and Coinbase in a culture built on shipping and ownership.
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.
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.
Meet Jack
What happens next?
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 your profile’s a match and StackOne wants to meet, Jill will make the intro. In the meantime, Jack will send you excellent alternatives.