Senior Software Engineer I - Ruby on Rails with Sidekiq

• Owning platform subsystems end to end: ingestion pipelines, sync reliability, normalization.
• Keeping the stack healthy: major framework and dependency upgrades, developer tooling, and the CI that keeps a small team fast.
• Taking of loosely specified problems (“this vendor’s FHIR implementation does something strange under load”) through diagnosis, design, and durable fixes.
• Keeping correctness and observability strong as the platform takes on new consumers.
• Pair with the engineer who built our sync and normalization systems and take ownership of one production pipeline, including its on-call. Your first shipped work will be a piece of the platform API or the internal tooling around it. By month three you’ll own a platform surface that other teams depend on.

• Current development skills with Ruby on Rails with Sidekiq on AWS (ECS, Aurora PostgreSQL), with a TypeScript frontend.
• Possess backend fundamentals: queues, retries, transactions, and the failure modes between them.
• Have real depth in SQL and relational data modeling, and the instinct to check the query plan.
• Possess End-to-end ownership of production systems, including the unglamorous parts.
• Have a debugging temperament: patient, methodical, happy in logs.
• AI-assisted development as a default: coding agents and spec-driven development are already part of how you work

3.83.8 out of 5 stars Philadelphia, PA $86,600 - $144,400 a year - Full-time

About Wellsheet at Elsevier: Wellsheet is a clinical decision support platform used by more than 20,000 providers across 100+ hospitals. We embed directly in the EHR (Epic, Cerner, Athena) and put AI-generated clinical context in front of clinicians at the bedside. In 2026 Wellsheet became part of Elsevier’s Clinical Solutions group, and we’re now building the next generation of our product: a new clinical AI experience shipping to our first hospital clients in early 2027, backed by an integration platform we’ve run in production for years. We’re a small, all-senior engineering team. You’ll own real surface area from your first weeks, work directly with the people who built the system, and ship software that clinicians use during patient care. No healthcare background is required. We train the clinical and interoperability domain; we hire for engineering judgment.

About the team The Platform squad runs the machinery underneath everything clinicians see: real-time EHR sync across Epic, Cerner, and Athena, FHIR ingestion for 100+ hospitals, and vocabulary normalization across 125+ clinical terminologies. The squad is led directly by the technical leader behind Wellsheet’s platform. Its next major build, which you’ll help kick off, is the platform API that other Elsevier clinical products and internal teams will consume. The squad also owns the internal tooling for managing the platform and the health of the stack itself, from framework upgrades to developer tooling.

Our stack today is Ruby on Rails with Sidekiq on AWS (ECS, Aurora PostgreSQL), with a TypeScript frontend where our tools need one. The work is mostly backend, but internal tools need real interfaces, and this squad builds its own. We don’t require prior experience in any of the stack.

About the role You will build the platform API alongside the squad lead: own endpoints, contracts, and the extraction work that turns internal seams into a real interface. You will also be building the internal tooling for managing the platform, frontends included: vocabulary mapping, data quality, hospital onboarding, and the operational views that let a small team run 100+hospitals, Elsevier is a renowned global information analytics company that primarily focuses on providing scientific, technical, and medical (STM) research content, tools, and services. It is one of the largest publishers of academic journals and scholarly literature in the world.

Elsevier operates in various domains, including science, technology, medicine, social sciences, and more. They publish a vast number of peer-reviewed journals covering a wide range of disciplines. These journals act as platforms for researchers and academics to share their findings and contribute to the advancement of knowledge in their respective fields. U.S. National Base Pay Range: $86,600 - $144,400. Geographic differentials may apply in some locations to better reflect local market rates.If performed in New York, the base pay range is $95,300 - $158,900.If performed in New York City, the base pay range is $103,900 - $173,300.If performed in Rochester, NY, the base pay range is $86,600 - $144,400.This job is eligible for an annual incentive bonus.