• 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.

• Migrate and re-architect legacy Perl batch jobs and crontab pipelines into modern Python-based services. • Design and implement orchestration using Prefect or Airflow, including alerting, observability dashboards, and safe job re-run capabilities. • Instrument services with structured logging and metrics (CloudWatch, or Grafana) to eliminate the need for direct production server access. • Manage the data layer for file ingestion: landing raw scheme files to S3, parsing/transforming them, and persisting to PostgreSQL or RDS for reconciliation. • Process and reconcile payment scheme files (clearing, settlement, chargebacks) from card schemes and acquirers. • Contribute to architecture decisions, write technical documentation, and establish best practices across the team.

• Support and extend the existing Perl-based payment gateway debugging production issues and adding features while migration is ongoing • Design, develop, and maintain modern server-side components in Python, ensuring high performance and scalability • Integrate third-party APIs and external payment services into both legacy and modern platform layers • Collaborate with multiple stakeholders across departments working in agile sprints • Maintain high code quality standards and contribute to a culture of continuous improvement • Work closely with DevOps on CI/CD pipelines, containerization, and cloud deployments