AI Research Engineer, StackOne
Model Training
+ Share options plan
2 days a week in office
Integration infrastructure for AI agents
Job no longer available
Integration infrastructure for AI agents
21-100 employees
Job no longer available
+ Share options plan
2 days a week in office
21-100 employees
Company mission
To build the integration infrastructure that lets AI agents act — securely, reliably, across any system.
Role
Who you are
- Background in deep learning, with emphasis on LLMs
- Experience running large-scale distributed training jobs
- Understanding of synthetic data techniques and dataset pipeline design
- Proficiency in evaluating LLMs with quantitative metrics and human evals
- Desire to work in a fast-paced startup, taking ownership of projects e2e and bias towards shipping
- (Preferred) Contributions to open-source ML libraries or published research in applied ML/LLM fine-tuning
What the job involves
- 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
- We are looking for an AI Research Engineer with deep expertise in large-scale model fine-tuning, dataset curation, and training infrastructure
- Unlike our AI Engineer role, which focuses on applying and productionizing existing LLMs and agent frameworks, this role is focused on pushing model performance through fine-tuning, synthetic data pipelines, and large-scale experimentation
- You will own, design and run experiments on cutting-edge architectures, manage distributed training clusters, and help curate & generate high-quality datasets
- This role sits closer to the research/ML infra side than product engineering, but with a strong mandate for applied, production-ready results
- In this role, you will work with wider AI team of StackOne (comprising of other researchers and engineers) and report directly to the CTO
- Own the full lifecycle of model fine-tuning projects (objectives, dataset prep, training, eval, deployment handoff)
- Design and manage synthetic data generation workflows to augment real-world datasets
- Build and maintain large-scale training infrastructure (multi-GPU/TPU clusters, orchestration, optimization)
- Develop tools for dataset curation, labeling, filtering, and augmentation
- Conduct benchmarking, and evaluations to measure fine-tuning impact
- Collaborate with the rest of the engineering team to integrate fine-tuned models into production stacks
- Stay ahead of research in parameter-efficient fine-tuning, synthetic data, and LLM training
- 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, Incident.io
- Languages & Frameworks: Typescript (Node.js), Python, NestJS, React, Svelte,
- Other day-to-day Tools: Postman, Notion, Slack, Jira, Github and more
Salary benchmarks
Our take
The explosion of SaaS tools has created an integration nightmare for companies. More and more B2B customers are expecting their SaaS tools to integrate with each other natively. But building and managing API connections in-house as a software vendor is time-consuming and costly, diverting teams from their core roadmap and stopping sales teams from selling.
As the next-generation integration platform, StackOne is solving the challenge of building SaaS integrations at scale once and for all. Founded in 2023 by ex-Google and Oracle executives, StackOne has seen exceptionally fast growth since its launch. With its best-in-class security and real-time architecture, the company is well-positioned to become a category leader in the API integration solutions market.
Steph
Company Specialist at Welcome to the Jungle
Company
Funding (last 2 of 3 rounds)
Apr 2025
$20m
Series A
Nov 2023
$3.6m
Seed
Total funding: $23.9m
Company benefits
- Meaningful share options (EMI) - share in the company's success as we grow
- 25 days holiday + 1 additional day per year of tenure
- 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
- 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
- Health, fitness and gift card discounts
- Cycle2Work and Electric Car Scheme
- Monthly in-person socials
- Annual team offsite to sunny spots (last ones were in Spain and Portugal!)
Company HQ
Central London
Articles
Leadership
Romain Sestier
(Co-Founder & CEO)Previously worked for Google as co-founder and Product Lead of Area120, VP of Product and Sales at Yieldify, co-founder and CEO of Upper.ai and Head of UK Professional Services at ContentSquare.
Guillaume Lebedel
(Co-Founder & CTO)Previously VP of Engineering at Yieldify until its acquisition by Epsilon/Publicis. Also co-founded another start-up and worked at Maxymiser (acq. by Oracle) as a developer.
Diversity, Equity & Inclusion at StackOne
Yasmin Chalmers (Head of People)
- Women @ StackOne community
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