Senior Software Engineer - LIMS Modernization

Onterris•Little Rock, AR

8d•$200,000 - $210,000

About The Position

At Onterris, we build careers grounded in purpose, responsibility and real-world impact. “For Planet and Progress” is our north star that guides everything we do. We believe environmental responsibility and human progress are interconnected, interwoven and international. Our scientists, engineers, field teams, consultants and professionals collaborate across disciplines and geographies, guiding industries and governments, ensuring that communities and environments thrive. When you join us, you’re not just forging a career, you’re joining a movement. A movement for better thinking, smarter solutions and lasting impact. Together, we will advance our way of life and protect the integrity of our environment every step of the way. CT LIMS is our most significant piece of custom-built enterprise software: a proprietary Laboratory Information Management System (LIMS) 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: codebase 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. You’ll reverse-engineer what exists, document it so any competent engineer can navigate it and help architect what comes next. One level down from owning the corporate transformation, you are the 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. This is not pure archaeology and it is not a blank page. It is both at once.

Requirements

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.

Nice To Haves

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.

Responsibilities

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 (boilerplate, syntax, archaeology), when to collaborate (domain logic) and when to write manually (data integrity, 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 and 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 the 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.