Senior Software Engineer

About Lithos

Lithos is the API layer for modern telehealth. Brands and clinics build their patient experience on our platform, and we handle the hard parts underneath: clinician review workflows, e-prescribing and pharmacy fulfillment, lab ordering, patient records, and the compliance machinery that makes it all safe. Partners integrate a documented public API and webhooks; their patients get care.

We're a small, senior team that ships quickly without cutting corners. Our codebase reads like it was written to be maintained for a decade: database constraints back every invariant, API contracts are generated and drift-checked in CI, and every non-obvious decision is documented where the code lives.

What you'll work on

• The core clinical platform: a Ruby on Rails API (PostgreSQL) modeling real clinical workflows as explicit state machines, with database-enforced lifecycle invariants, background job pipelines, and signed webhooks.
• The partner-facing public API: contract-first with OpenAPI, strictly additive versioning, and typed clients generated for our frontends. Partner-developer experience is a first-class product surface here.
• Clinician and operations consoles: Next.js + TypeScript applications for clinical review, prescribing, and back-office operations, built on a shared design system.
• Integrations that touch the physical world: e-prescribing, pharmacy fulfillment, lab networks, and document generation for clinical paperwork.
• Cloud infrastructure on GCP, with CI/CD pipelines, environment-per-stage deploys, and human-gated production releases.

What we're looking for

• 6+ years building production backend systems; deep comfort in Ruby on Rails (or an equivalent framework with the humility to learn ours) and PostgreSQL. You think in transactions, constraints, and idempotency, not just ORM calls.
• Strong TypeScript/React skills. You can carry a feature across the full stack, from migration to serializer to con