Senior Full-Stack Software Engineer – Applied AI

Mainstay

Senior Full-Stack Software Engineer developing AI-driven workflow management systems for Mainstay. Collaborate closely with teams to design and build scalable backend services and intuitive product experiences.

Posted 5/22/2026full-timeSan Francisco • California • 🇺🇸 United StatesSeniorWebsite

Tech Stack

Tools & technologies

PythonReact

About the role

Key responsibilities & impact

Contribute to all phases of product development, from ideation and prototyping to implementation and iteration
Design reliable, scalable backend services to support AI-powered features in production
Build and evolve scalable backend services and APIs that aggregate, enrich, and serve large, complex real estate datasets
Develop and refine frontend and backend product experiences that make sophisticated data intuitive, trustworthy, and actionable
Evaluate and benchmark LLM performance across latency, cost, accuracy, and hallucination rates
Own technical decisions for systems that sit at the center of Mainstay’s SaaS platform and directly influence investor decision-making
Partner closely with product managers, designers, data science, and data engineering to translate business needs into durable technical solutions
Improve system reliability, performance, and maintainability as the platform scales
Modernize and automate legacy real estate workflows by replacing manual analysis with software-driven insights
Mentor other engineers through code reviews, technical guidance, and shared ownership of team standards

Requirements

What you’ll need

5+ years of experience building and shipping production-grade software in fast-paced and early-stage start up
Proven, hands-on experience developing and deploying production-ready AI features
Highly proficient with AI-first thinking and software development best practices
Strong full-stack engineering skills with a backend-first orientation
Deep experience designing, building, and operating scalable backend systems, ideally in Python
Solid frontend experience with React or similar modern frameworks
Experience working with data-heavy, analytics-driven, or workflow-oriented systems
Strong technical judgment and the ability to balance speed, correctness, and long-term maintainability
Clear, thoughtful communication skills for a remote, highly collaborative team
A proactive, ownership-driven approach to ambiguous problems

Benefits

Comp & perks

Professional development opportunities
Flexible working arrangements

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills & Tools

PythonAI featuresbackend systemsAPIsReactfull-stack engineeringsoftware development best practicesdata analyticssystem reliabilityperformance optimization

Soft Skills

communication skillstechnical judgmentproactive approachmentorshipcollaborationproblem-solvingownership-driven mindsetthoughtful decision-makingcode reviewsteam standards