Senior Full-Stack Software Engineer

Full-Stack Senior Software Engineer What you should expect as a full-stack senior software engineer - maximum agency, tight feedback loops with customers, and no shortage of product challenges that directly translate to business value! You'll have the opportunity to design, build, and ship complex AI-powered workflow management systems and tools that enable our operations team to execute at scale.We're looking for someone who can use AI to efficiently ship features across the stack and ship reliable, production ready AI features end to end - from retrieval pipelines and guardrails to backend systems and user facing product experiences.Our products are built with Python, Typescript, and React on AWS.In this role you willContribute to all phases of product development, from ideation and prototyping to implementation and iterationDesign reliable, scalable backend services to support AI-powered features in productionBuild and evolve scalable backend services and APIs that aggregate, enrich, and serve large, complex real estate datasetsDevelop and refine frontend and backend product experiences that make sophisticated data intuitive, trustworthy, and actionableEvaluate and benchmark LLM performance across latency, cost, accuracy, and hallucination ratesOwn technical decisions for systems that sit at the center of Mainstay's SaaS platform and directly influence investor decision-makingPartner closely with product managers, designers, data science, and data engineering to translate business needs into durable technical solutionsImprove system reliability, performance, and maintainability as the platform scalesModernize and automate legacy real estate workflows by replacing manual analysis with software-driven insightsMentor other engineers through code reviews, technical guidance, and shared ownership of team standardsWhat we're looking for5+ years of experience building and shipping production-grade software in fast-paced and early-stage start upProven, hands-on experience developing and deploying production-ready AI featuresHighly proficient with AI-first thinking and software development best practicesStrong full-stack engineering skills with a backend-first orientationDeep experience designing, building, and operating scalable backend systems, ideally in PythonSolid frontend experience with React or similar modern frameworksExperience working with data-heavy, analytics-driven, or workflow-oriented systemsStrong technical judgment and the ability to balance speed, correctness, and long-term maintainabilityClear, thoughtful communication skills for a remote, highly collaborative teamA proactive, ownership-driven approach to ambiguous problemsThis role is a great fit ifYou want to work on high-leverage systems that directly shape how institutional investors deploy capitalYou enjoy owning complex technical problems from problem definition through production impactYou like working at the intersection of data, product, and business decision-makingYou're comfortable influencing technical direction and raising the bar for engineering qualityYou thrive in environments with autonomy, responsibility, and evolving priorities with strong ownershipNot a great fit ifYou lack strong backend experience or are uncomfortable owning production systems in PythonYou prefer narrowly scoped tasks over end-to-end ownershipYou avoid frontend or product-facing work You struggle with ambiguity, changing requirements, or close cross-functional collaborationYou prefer highly rigid processes and minimal iterationTools we useLanguages: Python, TypeScriptBackend: FastAPI, DjangoFrontend: React, Next.jsData: Airflow, dbt, Snowflake, PostgreSQLInfra: AWS, TerraformTooling: GitHubMainstay Built on Trust At Mainstay, trust is at the core of everything we do. We build trust with everyone -- from candidates to employees to partners. We believe in fairness and openness throughout our hiring process, evaluating candidates based on qualifications without regard to race, color, religion, national origin, age, gender, marital status, disability, veteran status, sexual orientation, gender identity, or any other protected status. Our privacy practices describe how we handle applicant information, you can find the policy details for California residents here.We are committed to providing reasonable accommodations throughout our recruitment processes for candidates with disabilities, pregnancy, religious beliefs, or other reasons protected by applicable laws. If you require assistance or a reasonable accommodation, please contact us at mainstay-recruiting@opendoor.com