At a Glance
- Tasks: Design and build AI features for seamless SaaS integrations.
- Company: Join StackOne, a fast-growing AI startup backed by top investors.
- Benefits: Enjoy share options, health insurance, and a generous holiday allowance.
- Other info: Flexible hybrid working and opportunities for career growth.
- Why this job: Be part of a team pushing the boundaries of AI technology.
- Qualifications: Experience in full-stack development with TypeScript/Python and LLMs.
The predicted salary is between 36000 - 60000 € per year.
About StackOne: StackOne is the AI Integration Gateway for SaaS products and AI Agents. Backed by GV and Workday Ventures ($24M raised), we help builders of SaaS platforms and AI Agents orchestrate hundreds of scalable, accurate, and enterprise-grade integrations. Our 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.
Join us on our fast trajectory to build the future of agentic integrations. With an AI-native integration toolkit that delivers real-time execution, managed authentication, granular permissions, and full observability, all built with safety at its core, we’re now doubling down on AI R&D & creating our own lab to push the boundaries of tool calling for agents: training specialized LLMs designed to outperform general-purpose models in what matters most: precision, reliability, and safety in agentic execution.
About the role: You’ll help build a world where users of any agents can integrate with the tool of their choice in one click thanks to StackOne. We are looking for a Software Engineer with a strong background in AI production-grade applications with professional experience working with LLMs (eg: GPT, Anthropic and others). In this role, you will deliver AI features and products end-to-end and work with the wider AI team of StackOne (comprising of AI researchers and other AI engineers). You will report directly to the CTO.
Responsibilities:
- Act as a full-stack engineer: design, build, and ship features across frontend, backend, and infrastructure.
- Leverage AI models to accelerate development, while maintaining best-in-class reliability, testing, and code quality.
- Build and maintain inference pipelines, embeddings, retrieval, and orchestration systems.
- Integrate tool-calling and MCP (Model Context Protocol) patterns into product features.
- Ship and maintain open-source or internal TypeScript/Python packages.
- Work with AWS and/or Cloudflare to deliver scalable, secure, low-latency systems.
- Collaborate with product and design to deliver features end-to-end.
What we’re looking for:
- Proven experience as a full-stack engineer.
- Expertise in TypeScript and/or Python.
- Strong background in building on AWS and/or GCP and/or Cloudflare.
- Experience building and shipping TypeScript/Python packages.
- Familiarity with tool-calling, agent frameworks, and MCP.
- Track record of shipping production systems with high code quality and reliability.
- Curiosity to push the boundaries of what AI-powered development can deliver.
- Past experience with Generative AI/LLMs and related technologies/frameworks.
- Desire to work in a fast-paced startup, taking ownership of projects e2e and bias towards shipping.
- (Preferred): Experience working on/publishing CLIs & SDKs.
Benefits:
- Meaningful share options (EMI) - share in the company's success as we grow.
- 25 days holiday + 1 additional day per year of tenure.
- Private health insurance - including dental & optical.
- £15/day lunch budget when working from our London office, up to £120/month.
- £1,000 for your home office set up + £500/year top-up.
- Annual team offsite to sunny spots (last ones were in Spain and Portugal).
- Join one of Europe’s fastest-growing startups.
- Work with a veteran team of ex-employees of Google, Microsoft, Oracle, Coinbase, JP Morgan and more.
- Health, fitness and gift card discounts.
- Cycle2Work and Electric Cars scheme.
- Hybrid working friendly - typically 2 days/week in our London office. We’re open to discussing flexible arrangements—please share any preferences in your application.
Ready to help us change the game for SaaS integrations? Get in touch and let's chat! We believe diversity drives innovation. We encourage individuals from all backgrounds to apply. As an equal-opportunity employer, we celebrate diversity and are committed to creating an inclusive environment for all employees.
AI Engineer in London employer: StackOne
StackOne is an exceptional employer, offering a dynamic work environment where innovation thrives. With meaningful share options, generous holiday allowances, and a strong focus on employee well-being, including private health insurance and a robust home office setup, we empower our team to excel. Our hybrid working model and commitment to diversity ensure that every voice is heard, making StackOne a fantastic place for AI Engineers to grow and contribute to the future of SaaS integrations.
StudySmarter Expert Advice🤫
We think this is how you could land AI Engineer in London
✨Tip Number 1
Network like a pro! Reach out to folks in the AI and SaaS space, especially those connected to StackOne. A friendly chat can open doors that applications alone can't.
✨Tip Number 2
Show off your skills! Create a portfolio showcasing your projects, especially those involving LLMs or integrations. This gives us a taste of what you can bring to the table.
✨Tip Number 3
Prepare for the interview! Brush up on your TypeScript and Python knowledge, and be ready to discuss how you've tackled challenges in past projects. We love seeing problem-solving in action!
✨Tip Number 4
Apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, we’re always on the lookout for passionate candidates who want to make an impact.
We think you need these skills to ace AI Engineer in London
Some tips for your application 🫡
Tailor Your CV:Make sure your CV reflects the skills and experiences that align with the AI Engineer role. Highlight your expertise in TypeScript, Python, and any relevant projects you've worked on, especially those involving LLMs.
Craft a Compelling Cover Letter:Use your cover letter to tell us why you're passionate about AI and how your background makes you a great fit for StackOne. Share specific examples of your work that demonstrate your ability to deliver production-grade applications.
Showcase Your Projects:If you've built any open-source projects or internal packages, make sure to mention them! We love seeing practical applications of your skills, especially if they relate to tool-calling or agent frameworks.
Apply Through Our Website:We encourage you to apply directly through our website. It’s the best way for us to receive your application and ensures you don’t miss out on any important updates from our team!
How to prepare for a job interview at StackOne
✨Know Your AI Stuff
Make sure you brush up on your knowledge of LLMs and generative AI technologies. Be ready to discuss your past experiences with these models, as well as any projects you've worked on that involved AI integration. StackOne is all about pushing the boundaries, so show them you're curious and passionate about AI!
✨Showcase Your Full-Stack Skills
Since the role requires a full-stack engineer, prepare to talk about your experience with both frontend and backend development. Have examples ready that demonstrate your expertise in TypeScript and Python, and be prepared to discuss how you've built and shipped production systems with high reliability.
✨Familiarise Yourself with Their Tech Stack
Get to know the tools and platforms mentioned in the job description, like AWS, GCP, and Cloudflare. If you have experience with tool-calling and agent frameworks, make sure to highlight that. Showing that you understand their tech stack will give you an edge in the interview.
✨Ask Insightful Questions
Interviews are a two-way street! Prepare some thoughtful questions about StackOne's vision for AI integrations and their plans for R&D. This not only shows your interest in the company but also gives you a chance to assess if it's the right fit for you. Plus, it demonstrates your proactive approach to understanding their goals.
