Senior Product Engineer, Scalability

Responsibilities

• Architect and scale pipelines that turn raw usage into accurate, real-time billing — metering, aggregation, rating, and invoicing across millions of events, from ingestion in ClickHouse to the rating engine
• Build payment flows that are correct under concurrency and partial failure: idempotent charges, retries, reconciliation, and clean handling of provider edge cases (Stripe and beyond)
• Develop fraud and abuse detection — signal collection, real-time scoring, automated mitigation — that protects platform margin without getting in legitimate users' way
• Scale the systems everything else depends on: Postgres under heavy write load, Node.js services under pressure, and long-running workflows orchestrated with Temporal where exactly-once semantics and durability actually matter
• Build TypeScript + GraphQL APIs where correctness and auditability are non-negotiable
• Write Engineering Requirement Documents to take something from idea, to defined tasks, to implementation, to monitoring its success and scaling it further
• Contribute to open-source repositories (CLI, Typescript SDK, Railpack, etc.) — Rust experience, or the desire to learn it, helps here
• Be oncall from time to time

Projects

• Re-architect billing end-to-end: per-second usage metering at platform scale, idempotent payment processing that survives provider outages without double-charging, and credit, prepayment, and enterprise-invoicing models that hold up under audit
• Stand up a fraud-detection service that scores signups and deployments in real time and automatically throttles abuse (crypto mining, free-tier farming, stolen cards)
• Scale Temporal workloads to orchestrate workflows across millions of deployments
• Build internal tooling that gives teams across Railway a trustworthy, real-time view into the systems they depend on

Requirements

• Ability to autonomously lead, design, and implement backend systems where correctness, consistency, and auditability are first-class requirements
• Track record of scaling systems — taken a pipeline, service, or database that was falling over and made it handle 10x
• Deep expertise in Postgres and relational data modeling — understand the cost of getting consistency guarantees wrong, and know how Postgres itself behaves at scale
• Strong working knowledge of Node.js internals — the event loop, memory behavior, and what to do when a service degrades under load
• Experience managing complex asynchronous and long-running backend jobs, ideally with a workflow engine like Temporal, for things like billing runs or payment reconciliation
• Familiarity with the realities of money movement: payment providers, idempotency, retries, reconciliation, and their failure modes
• Security and abuse-aware mindset — instinctively think about how a system can be gamed, and design accordingly
• Desire to be a part of the entire project development process, from research gathering and planning, to implementation and monitoring
• Great written and verbal communication skills for expressing ideas, designs, and potential solutions in a mostly-asynchronous manner

Nice-to-Haves

• Direct billing, payments, or fraud experience
• Rust experience, or the desire to learn it