Senior Software Engineer - LIMS Modernization

Onterris; United States; On-site; USD 200,000 - 210,000; Full time

Job summary

Onterris is seeking a senior software engineer to modernize CT LIMS. You will turn specifications and architecture decisions into working, tested software, partnering with Staff Engineers, labs developers, cloud and platform teams.

You will drive spec-first development and high-coverage tests, contributing to architecture readiness and comprehensive documentation of legacy components.

Qualifications

• 7+ years of professional software engineering experience.
• Strong cloud-native engineering fundamentals (Azure preferred).
• Experience with Spec-Driven and Test-Driven Development.

Responsibilities

• Engineer who translates specs and architecture into tested software.
• Document legacy system with diagrams and Mermaid.js.
• Develop architecture-ready, AI-assisted development workflows.
• Collaborate with Staff Engineer and platform teams to modernize CT LIMS.

Skills

7+ years of experience

Cloud-native engineering

Spec-Driven Development

Test-Driven Development

AI-assisted development

Documentation as code

Cross-team communication

Tools

Azure

Docker/Podman

Workday integration

Mermaid.js

GitHub Copilot

Job description

A Day in the Life

CT LIMS is our most significant proprietary Laboratory Information Management System that runs production operations across multiple Onterris labs and carries a live, real‑time Workday integration. It is a strategic asset despite its legacy codebase. The team is doing the disciplined work to decide this system’s future: code‑base archaeology, durable documentation and architecture readiness ahead of a modernization effort. The build starts fast. This is the engineer who helps make that build real. You’ll bring modern engineering rigor—Spec‑Driven, Test‑First, AI‑Augmented—to a system that has run for years on hard‑won domain knowledge and a long‑lived legacy codebase.

Your role is a senior builder who turns specs and architecture decisions into working, tested software. You’ll partner closely with the Staff Engineer, senior Labs developers, the cloud and landing‑zone team, the platform architects and lab leadership.

The compensation range for this role is $200,000 – $210,000 USD, commensurate with experience, skills, and geographic location.

Build through Spec‑Driven Development (SDD)

• Work “Blueprints Before Bricks”: the design is clarified in a Markdown specification before code is written.
• Author specifications and architecture‑as‑code in Markdown and Mermaid.js, committed to Git alongside the code.
• Help establish the templates and review habits that make spec‑first development the default.

Deliver test‑first development (TDD)

• Build the automated test coverage that lets the team move fast with confidence.
• Hold the line on coverage standards, particularly for AI‑generated code.
• Implement architectural guardrails that keep modular boundaries from eroding back into a monolith.

Use AI as a force multiplier

• Use Cursor and Claude Code as primary instruments for codebase archaeology, documentation and prototyping.
• Contribute to the .cursorrules and prompt libraries that encode our architectural standards.
• Apply judgment about when AI accelerates, when to collaborate, and when to write manually for data integrity and edge cases.

Reverse‑engineer and document the legacy system

• Produce module‑level documentation: purpose, inputs and outputs, dependencies, data models and known technical debt.
• Build data‑flow diagrams for the sample lifecycle, Workday integration, billing and invoicing triggers, instrument interfaces and user authentication and authorization.
• Contribute to the integration inventory and technical‑debt register, triaging components as Fix Now, Doc, Defer or Accept Risk.

Contribute to architecture and cloud readiness

• Help shape CT LIMS placement within our Azure landing zone and environment tiers (production, non‑production, sandbox).
• Contribute to high‑availability and hybrid on‑prem design, including instrument‑integration constraints that require a local network presence.
• Partner with the Staff Engineer, the cloud and landing‑zone owner and the platform architects so the modernization aligns with adjacent Onterris platforms rather than duplicating them.
• Develop reference implementations and prototypes that de‑risk the architecture choice while it is still being made.
• Help the team move from “ready to start” to “shipping” without a standing start if the modernization is approved.

What Success Looks Like

• A senior engineer with no prior CT LIMS exposure can navigate the system from your documentation alone, and it holds up under structured review.
• Spec‑Driven and Test‑Driven Development is simply how you work. Specs and tests precede code, and it shows in the quality of what ships.
• The legacy components you’ve touched are documented, diagrammed in Mermaid and committed to Git. No tribal knowledge, no binary files.
• AI‑assisted workflows you’ve helped build are reused across the team, not one‑off.
• Reference implementations exist for the riskiest parts of the target architecture and rest on evidence, not opinion.
• You’re contributing production modernization code within the first 90 days, not still ramping up.

Your Expertise and Skills

• 7+ years of professional software engineering experience.
• Strong cloud‑native engineering fundamentals (Azure preferred; AWS or GCP equivalent acceptable).
• Demonstrated practice with Spec‑Driven and Test‑Driven Development, clean architecture and domain‑driven design.
• Hands‑on experience with AI‑assisted development tools (Cursor, Claude Code, GitHub Copilot or similar).
• Ability to read, reverse‑engineer and reason about an unfamiliar or legacy codebase you did not write.
• Comfortable producing documentation and diagrams as code (Markdown, Mermaid.js) versioned in Git.
• Strong communication. You can explain the “why” to experienced engineers and partner effectively across teams.
• You respectfully challenge your peers, and welcome the opportunity when others challenge you.
• You are flexible, resilient and curious.
• You understand prior art but are compelled to iterate beyond it.

Preferred Experience

• Experience reverse‑engineering or maintaining systems written in Perl or another long‑lived legacy language.
• Background in LIMS, scientific or other regulated and compliance‑driven software (EPA reporting, chain‑of‑custody, lab accreditation).
• Experience with Oracle, and with evaluating database migrations (for example, toward PostgreSQL and or Snowflake).
• Familiarity with containerization (Podman or Docker) and hybrid on‑prem and cloud deployment patterns.
• Exposure to enterprise integrations such as Workday.
• Familiarity with prompt engineering and AI workflow optimization.

We are an equal‑opportunity employer and encourage applications from people of all backgrounds. We are committed to providing access and reasonable accommodation in our employment for all applicants.

For US residents, click here to learn more.

For more information, visit www.onterris.com.