About StackOne

StackOne is the universal integration gateway for modern SaaS products and agents. Weve raised $24m in 2 years and were backed by top tier investors like Google Ventures and Workday Ventures.

StackOne sits behind the scenes as the integration layer providing thousands of tools: SOC 2 compliant multi-tenant and invisible to end users powering integrations for future-of-work SaaS categories such as HR Compliance and AI Agents.

Our customers are established B2B SaaS companies or small to enterprise companies building Agents to sell or to improve their own processes.

About the role

Were building a world where users of any SaaS can integrate with the tool of their choice in one click thanks to StackOne. Were convinced AI is pivotal to making this a reality by transforming how SaaS talks to each other and this is what you will help achieve.

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 were 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

Our Stack

You will have a lot of freedom and agency to chose and work with the technologies you love. Our tech stack includes:

• Infra & monitoring: AWS (ECS RDS Elasticache Lambda etc.) Cloudflare Tinybird Modal Dagster Langsmith Datadog Sentry

• Languages & Frameworks: Typescript () Python NestJS React Svelte

• Other day-to-day Tools: Postman Notion Slack Jira Github and more

Benefits

• 25 days holiday 1 additional day holiday per year of tenure

• Participation in the companys employee share options plan

• Private health insurance (including dental & optical)

• Health fitness and gift card discounts

• 1000 for your home office set up 500/year top-up

• Paid lunch in the office

• Annual team offsite to sunny spots (last ones were in Spain and Portugal )

• Join one of Europes fastest-growing startups

• Work with a veteran team of ex-employees of Google Microsoft Oracle Coinbase JP Morgan and more

• Cycle2Work and Electric Cars scheme

• Hybrid work set up - typically 2d in the office

Ready to help us change the game for SaaS integrations Get in touch and lets 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.