# AI Research Engineer

**Company:** [PostHog](https://hotfix.jobs/companies/posthog)
**Location:** Unspecified
**Role:** AI Research
**Skills:** PyTorch, Rust, CUDA, C, Transformers, Machine Learning, Deep Learning, Mathematics
**Posted:** 2026-08-18

> Researches and productionizes machine-learning models for session replay analysis, user behavior prediction, and synthetic testing. The role requires strong mathematics, PyTorch, systems programming in Rust/CUDA/C, and a product-oriented approach to shipping.

## Job Description

## Responsibilities

- Research and develop models for PostHog’s self-driving product and Deep ML systems.
- Bring research innovations into production with a strong focus on shipping usable products.
- Explore session replay analysis using DOM mutation data to improve speed, cost, and scalability.
- Develop user behavior prediction systems to identify drop-offs, suggest improvements, and potentially improve conversion rates.
- Investigate synthetic user testing to detect confusing flows or breakages before release.
- Work closely with customers and influence the products shipped by a new AI Research team.

## Requirements

- Strong background in mathematics, or previous experience training models; strong math skills are required in either case.
- Strong experience with PyTorch.
- Strong ability to code in Rust, CUDA, or C; Rust is preferred.
- Solid understanding of Transformers.
- Product mindset and willingness to build and ship products.

## Nice to Have

- PhD.

## Compensation and Benefits

- Hybrid-remote position based out of the London office.

## Exclusions

- This is not a purely theoretical or Jupyter-notebook-focused role.
- Research and publishing are supported, but shipping takes priority.

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