AI Research Engineer

What you'll be doing

You'll be part of a team that does research into what's next, what's better, and actually bring that in production.

Areas we’re exploring

• Session replay analysis:
 We already detect issues in replays, but it’s expensive and doesn’t scale. With better models (and a huge amount of DOM mutation data), we think we can make this faster, cheaper, and best-in-class.
• User behavior prediction:
 Identifying drop-offs, suggesting improvements, and potentially improving conversion rates automatically without heavy manual analysis or agent overhead.
• Synthetic user testing: 
Simulating users to catch confusing flows or breakages before release. If this works, it could remove one of the biggest bottlenecks in modern engineering: testing (not writing code anymore).

Job Requirements

• PhD is a plus, a strong background in math is a need
• or you have worked on training models previously (strong math skills are still a need)
• Strong Pytorch experience
• Strong ability to code in Rust, CUDA, or C (Rust has a preference)
• Solid understanding of Transformers (not the movies)
• A product mindset, you’ll be building things!
• This is a unique role within PostHog and as such it is Hybrid Remote at the London Office

What we’re not looking for

• Pure theoretical expertise, this is not a Jupyter notebook job
• Someone who just wants to do research and publish. Yes you can publish, but shipping has priority…