AI Research Engineer

• Join a brand-new AI Research team at PostHog, the only platform that acts as a co-pilot for product development and AI agents. • Play a substantial part in training deep ML models using petabytes of data across events, errors, session replays, revenue data, and more. • Have real autonomy, be close to customers, and greatly influence what actually ships in a team that researches what's next and brings it into production.

• Have a strong background in mathematics, or previous experience training models with strong maths skills. • Have strong PyTorch experience. • Have strong ability to code in Rust, CUDA, or C, with a preference for Rust. • Have a solid understanding of Transformers. • Have a product mindset — you'll be building things that ship to production.

• Hold a PhD in a relevant field.

• Research and build models for session replay analysis, making issue detection faster, cheaper, and best-in-class using DOM mutation data. • Work on user behaviour prediction to identify drop-offs, suggest improvements, and potentially improve conversion rates automatically. • Explore synthetic user testing to simulate users and catch confusing flows or breakages before release. • Bring research into production, with shipping taking priority over publishing. • Work with an exceptionally large dataset relative to company size, spanning events, errors, session replays, and revenue data across petabytes.

We have used PostHog's web analytics ourselves and genuinely loved the experience. The product is fast, thoughtfully designed, and surprisingly fun to use. PostHog is unlike most SaaS companies: their entire handbook is public, their codebase is open source, and they share revenue figures and board meeting notes with every team member. The company has raised $194M from investors, including Stripe, GV, and Y Combinator, reached a $1.4 billion valuation in 2025, and is targeting $100M in ARR by the end of 2026. They pay generously, benchmarking engineering salaries at the 90th percentile of San Francisco rates adjusted by location, with a fully public compensation calculator so you know your salary before you even apply. Employees on Glassdoor consistently highlight the flexible spending, genuine remote-first culture, and regular offsites, alongside a $1,500 quarterly budget for meeting up with colleagues anywhere in the world. Many team members are former founders, and the company is structured around small, autonomous teams that own their products end-to-end. If you are an engineer or builder who thrives on autonomy, ships fast, and wants to work on a product used by nearly 200,000 teams, PostHog is a rare opportunity.

• Receive generous, transparent compensation with significant equity. • Take unlimited vacation with a minimum requirement. • Enjoy two meeting-free days per week. • Receive a home office budget and coworking credit. • Access private health, dental, and vision insurance. • Get a training budget for professional development. • Receive pension contributions. • Attend company offsites and access the PostHog Hedge House.

PostHog is the only platform that acts as a co-pilot for product development and AI agents. Starting with open-source product analytics out of Y Combinator's W20 cohort, PostHog has since shipped more than a dozen products including PostHog Code, a built-in data warehouse, and PostHog AI. More than 450,000 organisations have installed PostHog, mostly driven by word-of-mouth. PostHog has raised more than $180m and has around $150m on the balance sheet, running efficiently with good margins for six years.