Backend Engineer

Summary

Join PostHog's Feature Flags team as a high-performance API engineer and build systems that respond in single-digit milliseconds at scale. You will own the entire feature flags evaluation engine, from design and build to deployment and scaling. This role offers the unique opportunity to work from first principles, setting your own performance targets and seeing immediate results. The ideal candidate has experience with high-throughput, low-latency services and a strong understanding of performance optimization techniques. PostHog is a fully remote company with a globally distributed team, currently hiring within GMT-8 and GMT+2 time zones. We offer a generous compensation package and a variety of benefits.

Requirements

• Experience with Python, Node, and ideally Rust. Our app is written in Django but the flags evaluation API is written in Rust so you'll be working between the two languages
• You have experience building systems that handle high volumes of requests/data (millions+ per minute)
• You can choose a sensible architecture quickly, and then ship it faster than other people think is possible
• Strong understanding of performance optimization techniques, caching strategies, and distributed systems principles

Responsibilities

• Own the entire service from end-to-end: Design, build, deploy, and scale the complete feature flags evaluation engine
• Build in the hot path with real impact: Your code runs in the critical path of our customers' applications, making a direct impact on their user experience
• Start from first principles: Scale up new services from the ground up rather than just maintaining existing infrastructure
• Set your own performance targets: You won't be constrained by other teams' requirements - you'll define and own the latency goals that make our customers successful
• See immediate results: Deploy optimizations and see the impact on performance metrics in real-time
• Work with cutting-edge tech: Our evaluation engine is written in Rust for maximum performance, while our application layer uses Python/Django
• Build and maintain our feature flags evaluation engine that makes complex decisions based on person/group properties at high speed and scale
• Work on a critical part of our infrastructure that customers rely on for real-time feature delivery
• Make high-level architecture decisions
• Optimize a performance bottleneck that slashes latency by 50%
• Work directly with customers to implement complex targeting rules that meet their specific needs

Preferred Qualifications

• Experience with feature flag systems or similar real-time decision engines
• You've carried a pager and have dealt with incidents
• You're comfortable with provisioning and deploying infrastructure
• Experience with benchmarking and profiling tools
• Knowledge of observability systems and practices

Benefits

• Generous, transparent compensation and employee-friendly equity in PostHog
• Unlimited time off with a 25-day minimum (in 2021 the team on average took 32 days off)
• Private medical insurance, including dental and vision (US and UK only)
• Pension/401k contributions (4% matching)
• Generous parental, bereavement and child loss leave
• Training budget and free books
• $200/month budget towards co-working or café working and $300/month for team socials
• Spill mental health chat
• $100/month budget to provide support to open-source projects
• We'll be your first investor
• Regular team off-sites (we went to Iceland in March) with carbon offsetting for work travel with Project Wren