Senior Site Reliability Engineer

About Pylon America’s $13T mortgage market is one of the most important financial systems in the world. It underwrites the middle class and is the mechanism through which millions of families build wealth. But while every other financial instrument has been simplified to an API call, mortgages are still assembled by hand. We started from zero and created the first vertically integrated mortgage platform that turns origination into a single API. Publicly traded companies and the country’s largest originators are already building on Pylon. Revenue is compounding monthly. We’re backed by Peter Thiel, Conversion Capital, QED, Citi, Fifth Wall, and the founders of Ramp, Blend, and Mercury. Working at Pylon isn’t for those seeking comfort. The people who thrive here have high agency, strong opinions, and a track record of delivering outcomes without direction. Many of us are former founders. We move quickly, challenge each other directly, and take full ownership of results. It’s hard work, but it will be worth it. Join us in building America’s mortgage rails. ABOUT THE JOB You'll own reliability and operational excellence for Pylon's production systems. This means designing and implementing monitoring, alerting, and incident response processes that scale as we grow. You'll build tooling that makes the entire engineering team more effective, establish on-call rotations and runbooks, and ensure our platform can handle the demands of a regulated, high-stakes financial product. This is not a pure ops role. At Pylon, we believe SRE work should be a maximum of 50% operational toil. If you're spending more than half your time firefighting and keeping things running, you're not doing SRE work, you're doing sysadmin work. The other 50%+ of your time should be spent writing code: building infrastructure tooling, automating away operational burden, making reliability improvements to core services, and creating internal developer productivity tools that make the entire team more effective. SRE is about making things better, not just keeping them alive. We're looking for someone who has operated production systems at scale in a professional engineering environment. You know what good looks like because you've built it before. WHAT WE'RE LOOKING FOR Must-haves: - 4+ years experience in SRE, infrastructure, or platform engineering roles - Experience working on a team of SREs at a company with mature SRE practices (not solo SRE roles) - Real on-call experience at scale in a large production environment (you've carried the pager and lived through incidents) - Deep AWS expertise (ECS, RDS, networking, security) - Strong experience with declarative infrastructure (Terraform, CDK, or similar) - Nix experience (we use it and want to expand its adoption) - Track record of building reliability tooling and automation - Can design and implement monitoring, alerting, and observability systems from first principles - Comfortable working in a regulated environment where "breaking things" is not an option Nice-to-haves: - Experience at companies with strong SRE cultures (Google, Replit, Stripe, etc.) - Background in fintech, healthtech, or other regulated domains - Experience migrating monitoring systems or implementing SLOs - Contributions to infrastructure tooling or open source projects OUR TECHNOLOGY STACK: We don't require that you've worked with any of these technologies before, this is just our stack for your information: - Infrastructure: AWS (ECS, RDS, CloudFront, Lambda), CDK for infrastructure-as-code - Observability: Honeycomb, OpenTelemetry - CI/CD: GitHub Actions, Nix for builds and dev environments - Core platform: TypeScript/Node backend, PostgreSQL, React frontend - Languages: TypeScript, Python, Nix, SQL ABOUT YOU You: Have operated production systems at scale. You've been on-call for a large, complex system. You know what 3am pages feel like and you've built systems to prevent them. You understand the difference between alerts that matter and