AI Research Engineer

• Join a brand new AI Research team at PostHog, working on training deep ML models using petabytes of product data spanning events, errors, session replays, and revenue. • Work on high-impact research areas including session replay analysis, user behaviour prediction, and synthetic user testing — and ship production models, not just papers. • Have real autonomy over what gets built, with direct customer exposure and significant influence over what the team ships. • Work at the intersection of research and engineering — this is not a Jupyter notebook job, it's about getting models into production. • Contribute to PostHog's mission of building a self-driving product that automatically surfaces insights and suggests fixes.

• Have a strong background in mathematics — this is a hard requirement. • Have strong PyTorch experience. • Have strong ability to code in Rust, CUDA, or C, with Rust preferred. • Have a solid understanding of Transformers. • Have a product mindset — you'll be building and shipping, not just researching. • Have previously worked on training models, or hold a PhD (PhD is a plus, not required). • Be committed to shipping — publishing is welcomed but shipping takes priority.

• Hold a PhD in a relevant field such as machine learning, mathematics, or computer science. • Have experience with large-scale data pipelines or petabyte-scale datasets. • Have experience with session replay analysis, user behaviour modelling, or synthetic testing systems. • Have experience working in a small, autonomous engineering team.

• Train and ship deep ML models using PostHog's large-scale product data. • Research and improve approaches for session replay analysis, user behaviour prediction, and synthetic user testing. • Bring research from exploration through to production deployment. • Work closely with customers to understand problems and validate solutions. • Contribute to defining the direction and roadmap of a brand new AI Research team. • Collaborate asynchronously within a remote-first, fast-shipping engineering culture.

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 significant equity in a well-funded, default-alive company with $150M+ on the balance sheet. • Access unlimited paid holiday with a guaranteed minimum. • Enjoy two meeting-free days per week (Tuesdays and Thursdays) for focused building time. • Receive a home office budget and coworking credit. • Access private health, dental, and vision insurance. • Receive a training budget and pension contributions. • Attend company offsites and access PostHog's Hedge House. • Work with full transparency — board notes, revenue figures, and fundraising plans are shared with everyone.

PostHog is the operating system for software builders — shipping every product companies need from day one to IPO and beyond. Starting with open-source product analytics out of Y Combinator W20, PostHog has grown to over 100,000 companies and a suite of more than a dozen products. The new AI Research team is building deep ML models on petabytes of product data to create a self-driving product that automatically surfaces insights, predicts user behaviour, and suggests fixes.