Staff Engineer, Full-Stack

SonderMind•Denver, CO

About The Position

As a Staff Engineer, you’ll own end-to-end features across one or more of our backend services, agentic frameworks, AI Pipelines and front end. You’ll work under minimal supervision, troubleshoot complex problems, come up with innovative designs and optimizations and help shape our microservices architecture while collaborating closely with product, design, and QA. You will work with high performance, mission critical tools and services. You do not need to have experience training or developing ML models/algorithms, but experience with them is a plus. What does success look like? 30 days: Ship a backend feature and demo it to the team 60 days: Potentially lead a cross-team API enhancement or propose a performance or scaling or testability improvement 90 days: Lead a system-level architectural improvement or completely new deliverable (e.g., introduce a TypeScript microservice or refactor a critical service for scalability), including a clear design, implementation, and rollout plan in place or executed against.

Requirements

8+ years building web services or full-stack applications
Strong hands-on experience in Ruby/Rails, TypeScript/Node, Python or similar backends
Deep understanding of APIs, PostgreSQL, and some performance tuning
Proven ability to balance short-term delivery with long-term technical investments and continuous improvement of quality.
Comfortable working in a fast-paced, ambiguous environment where requirements evolve over time.
Excellent problem-solving, communication, and collaboration skills
Familiarity with job-relevant AI platforms such as Gemini, ChatGPT, Claude, GitHub Copilot or other industry-standard AI productivity tools is expected and considered essential for success at this company.

Nice To Haves

Some knowledge of of AI/ML is desired but not a requirement
Experience with LLMs or AI-driven toolchain (Langchain/Langgraph) is highly desirable
Experience training or developing ML models/algorithms is a plus

Responsibilities

Design, build, and maintain scalable Ruby/Rails, TypeScript/Node, and Python services and RESTful or gRPC APIs that integrate with agentic GenAI systems
Optimize MongoDB and PostgreSQL queries and service performance
Collaborate with cross-functional squads to define requirements and deliver features
Work on AI Agents, MCP servers and various other AI enabled tools and frameworks and so must be comfortable working with ambiguity and rapidly evolving technologies
Identify and drive process, architecture, and toolchain improvements
Mentor junior engineers (code reviews, pair-programming etc)
Serve as a technical lead for complex projects, balancing scope, risk, and not compromising deliverable quality.

Benefits

A generous PTO policy, with a minimum of three weeks off per year
A holiday schedule that follows standard U.S. holidays
Free therapy coverage benefits to ensure employees have access to the care they need (must be enrolled in a qualifying medical plan to participate)
Competitive Medical, Dental, and Vision coverage, with plans to meet every need — including HSA (with $1,100 company contribution) and FSA options
Employer-paid short-term disability, long-term disability, life & AD&D, plus coverage of the salary difference for up to seven weeks of short-term disability leave (after the required waiting period)
Eight weeks of paid Parental Leave; if the parent also qualifies for STD, this benefit is in addition, allowing for 8–16 weeks of paid leave
401(k) retirement plan with 100% match on up to 4% of base salary, immediately vested
Join teammates from across the country at our annual company gathering
Company shutdown between Christmas and New Year’s
Supplemental life insurance, pet insurance, commuter benefits, and more