• Build, improve, and operate backend services that power LaunchDarkly’s Flag Delivery systems. • Contribute to systems that support streaming and polling delivery models for LaunchDarkly SDKs. • Debug production issues, improve service reliability, and help the team maintain strong standards around latency, availability, observability, and operability. • Work with technologies and patterns common to modern distributed backend systems, including caching layers, network services, concurrency, failure handling, and cloud infrastructure. • Collaborate closely with partner teams including SDK, Platform, SRE, Security, and Enterprise to deliver improvements across the broader platform. • Participate in the on-call rotation and take ownership of the systems you help build. • Learn the existing architecture deeply and make pragmatic improvements that increase system clarity, performance, and maintainability. • Use AI as part of your engineering workflow with sound judgment, including knowing when to use it, how to direct it effectively, and how to verify or reject its output. • Reason clearly about code, architecture, and whole-system behavior even when AI is in the loop.

• Design, build, and maintain scalable backend services using Elixir and Phoenix. • Develop highly available APIs and distributed systems that power critical platform functionality. • Build and optimize data pipelines, workflows, and background job processing systems. • Collaborate with AI, Data Science, and Product teams to bring intelligent automation capabilities into production. • Improve system observability, monitoring, reliability, and operational excellence. • Participate in architectural discussions and influence technical direction across the platform. • Help establish engineering best practices around testing, deployment, performance, and maintainability. • Mentor engineers and contribute to a collaborative, high-performing engineering culture. • Leverage AI-assisted development tools to improve productivity, quality, and delivery velocity.

• You'll help build PostHog's observability suite: Logs (live and growing fast), Traces (in alpha), and Metrics (landing soon); the products that let our customers, and their AI agents, understand, debug, and self-heal their own software. • This is the foundation for self-driving, self-healing products, and we're building most of it from scratch. The core challenge is easy to say and hard to do: ingest, store, and retrieve enormous volumes of telemetry; fast, reliably, and cost-effectively. Getting data in is the easy half; getting it back out efficiently at petabyte scale, without melting the infra bill, is the real game. We're already handling terabytes of data and it's growing! • You won't be maintaining a corner of someone else's system. You'll own a product area end-to-end, taking it from alpha -> beta -> GA, making the architecture calls, and shipping in the hot path where your code decides whether customers have a good day. You'll work across all three products and go deep on one.

• Legacy Modernisation: Read legacy code (PHP, Perl, or JavaScript), extract the business logic, and reimplement it correctly within a modern microservices architecture. • Reliability First: Ensure idempotency, data integrity, and graceful error handling across all services — "almost working" is never good enough. • Greenfield & Refactoring: Split your time between building new features from scratch and refactoring existing legacy modules into clean, maintainable code. • API Engineering: Design and consume external APIs with a deep understanding of webhooks, callbacks, and complex retry policies. • Agile Collaboration: Maintain clean and strong English communication to effectively collaborate with multiple stakeholders across departments working in agile sprints. • Product Thinking: Go beyond the "what" and "how" of the code — bring a product-focused mindset to understand the business logic and end-user impact of what you build. • Infrastructure Contribution: Contribute to CI/CD pipelines, Docker, or Kubernetes infrastructure where relevant. If you have a passion for infra, you are more than welcome to bring it. • Innovation: Propose and advocate for tools or technologies that can demonstrably improve our performance, security, or development speed.