Senior Full-Stack Engineer

Simulations Plus • US,

6d • $90,000 - $110,000 • Remote

About The Position

The Senior Full-Stack Engineer is a versatile contributor, part of a small department whose charter spans both web/SaaS and AI/agents products. The role will ship features across the full stack — backend, frontend, and LLM-integrated surfaces — wherever the team's most pressing implementation work lands in a given cycle. It's a high-variety role for an engineer who wants to build real depth across web platform and applied-AI engineering, on a deliberately lean team that's growing quickly and intentionally.

Requirements

• 3+ years of professional software engineering experience, with shipped full-stack work in production
• Proficiency in JavaScript or TypeScript across Node.js backend and React frontend
• Practical experience with document or NoSQL databases such as MongoDB
• Comfort building and consuming REST APIs and JSON contracts
• Genuine interest in agents, MCP, and applied AI, and the drive to build real expertise in those areas
• Fluency using AI coding tools (Claude, Cursor, Copilot) in daily workflow

Nice To Haves

• Familiarity with Anthropic, OpenAI, or other LLM provider SDKs
• Exposure to MCP, agent frameworks, or LLM-integrated product features
• Experience with cloud infrastructure (AWS preferred) and CI/CD pipelines
• Experience in regulated-software environments (SOC 2, HIPAA, GxP, 21 CFR Part 11) or life-sciences SaaS
• Familiarity with Passport, OAuth, OIDC, or comparable auth patterns

Responsibilities

• Own features end-to-end across Node.js and Express backends and React/Tailwind frontends
• Build the APIs, UI, and data flows behind real customer-facing functionality
• Contribute to the data, auth, and service patterns the platform builds on
• Integrate LLM-powered functionality into product surfaces, working alongside the team's AI lead
• Wire frontends to LLM and MCP endpoints; handle streaming, errors, and degraded states gracefully
• Contribute to evals, fixtures, and tooling that support the AI side of the team
• Bring full-stack range to a team that values flexibility across backend, frontend, and AI
• Contribute to code reviews, documentation, and the team's shared engineering practices
• Apply AI coding tools effectively as part of daily engineering workflow
• Other Duties as Assigned

Benefits

• fully remote work
• flexible schedules
• generous vacation policy
• affordable health coverage
• annual bonus

What This Job Offers

• Job Type: Full-time
• Career Level: Senior