AI Engineer

StackOne
London
About StackOne

StackOne is the universal integration layer for modern SaaS products. We've raised $24m in 2 years, and we're backed by top tier investors like Google Ventures and Workday Ventures.

Our unified API platform lets vendors ship hundreds of native, white label integrations in days, not months, by abstracting away dozens of disparate third party APIs into a single, normalized interface. On top of those APIs, we provide AI Agent Actions so customers can build agentic workflows without wrangling OpenAPI specs.

StackOne sits behind the scenes as an embedded iPaaS: 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 that:
  • Sell to mid market and enterprise buyers
  • Are building AI Agents in the near future
  • Need deep, native integrations to win competitive deals and power their product
  • Value time to integration over building connectors in house
We typically close OEM and embedded licensing deals, multi-year (1 to 3 year) contracts, five to seven figure TCV, with a strong land and expand model. Key buyer personas are the CPO and CTO.

About the role

We are looking for a Software Engineer or Data/AI Scientist with a strong background in AI production-grade applications with strong experience with LLM models (eg: GPT, Anthropic and others).

In this role, you will conduct research and development around AI, focusing on automating processes and development at StackOne. We're building a world where users of any SaaS can integrate with the tool of their choice in one click thanks to StackOne. We're 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.
Responsibilities
  • Research, design, and develop AI models using or training existing or bespoke LLM models (and other AI tech) to improve and automate API & more generally SaaS interactions.
  • Managing and updating Data pipelines used for AI use-cases
  • Collaborate with cross-functional teams to identify opportunities for AI integration and automation
  • Optimize and refine existing AI models and applications for performance and scalability
  • Stay current with advancements in AI and LLM technologies, applying new knowledge to StackOne's AI strategy
  • Implement best practices in AI development, ensuring compliance with data privacy and security regulations
  • Document and communicate research findings and development progress to stakeholders
  • Collaborate with other software & AI engineer(s) to deliver larger scale projects
Requirements
  • Bachelor's degree in Computer Science, Engineering, or a related field (or 3+ years of relevant experience)
  • Familiarity with API development, integration, and SaaS platforms
  • Past experience with AI, specifically Large Language Models and related technologies
  • Excellent problem-solving and analytical skills
  • Strong communication and collaboration abilities
  • Desire to work in a fast-paced, dynamic startup environment
Preferable:
  • You're familiar with Typescript
  • You've deployed or managed infrastructure on AWS
Our Stack

Y ou 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.), Tinybird, Modal, Dagster, Langsmith, Datadog, Sentry, Incident.io
  • Languages & Frameworks : Typescript (Node.js), NestJS, Rails, React, Svelte,
  • Other day-to-day Tools: Postman, Notion, Slack, Jira, Github and more
Product

StackOne is one of the fastest-growing embedded integration platforms. Here's why:
  • It drives down the cost of building integrations by 10x . To add dozens of integrations, you only need to integrate once with our unified API and we take care of the rest. This is way faster, cheaper, and more reliable than building every integration to each tool one at a time (it can take weeks/months per integration).
  • It has a superior architecture : Unlike other Unified APIs, we developed an innovative, fully real-time architecture that does not store their customers' sensitive data by default. This enables our customers to differentiate themselves on the market with better integrations: better for privacy, better for their product's user experience, and deeper read/write integrations.
  • StackOne is a better long-term partner : We are the only integration platform to guarantee new integrations as standard, that offers so many sandboxes to support testing and deploying faster, and that has built a strong partnership ecosystem to enable our customers to develop stronger commercial partnerships.
Benefits
  • 25 days holiday + 1 additional day holiday per year of tenure
  • Participation in the company's employee share options plan
  • Private health insurance (including dental & optical)
  • Health, fitness and gift card discounts
  • £1,000 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 Europe's 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 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.
Posted 2025-09-07

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