Senior Product Engineer: Scalability

You'll own your work end-to-end, including when a feature reaches the UI.

For this role, you will:

• Architect and scale the 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 our open-source repositories (CLI, Typescript SDK, Railpack, etc.) — Rust experience, or the desire to learn it, helps here.
• Be oncall from time to time.

Some projects this team takes on:

• 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 our 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.

This is a high impact, high agency role with direct effect on company culture, trajectory, and outcome.

About you

• An ability to autonomously lead, design, and implement backend systems where correctness, consistency, and auditability are first-class requirements.
• A track record of scaling systems — you've taken a pipeline, service, or database that was falling over and made it handle 10x, and you know which tools to reach for (and when polling stops being enough).
• Deep expertise in Postgres and relational data modeling — you reach for the right consistency guarantees, understand the cost of getting them 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. Direct billing, payments, or fraud experience is a strong plus.
• A security and abuse-aware mindset — you instinctively think about how a system can be gamed, and you design accordingly.
• A 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.

We value and love to work with diverse persons from all backgrounds.

Things to know

For better or worse, we're a startup; our team dynamics are different from companies of different sizes and stages.

• We're globally distributed—and getting more so. Stuff is always happening somewhere.
• We don't expect you to be online all the time, but you'll need to be diligent about your boundaries — your end of day will overlap with someone else's start.
• We're a small, high-ownership team that cares deeply about doing exceptional work. We're scaling quickly, which means we rely on leverage—systems over coordination, judgment over process. Expect ambiguity and a fast-moving environment.
• You'll own real outcomes. That means making decisions, not just executing—and owning the success, or failure, that comes with them.