Senior Fullstack Engineer

Senior Fullstack Engineer Your Opportunity: We're building a category-defining company at the intersection of real estate, technology, business services, and the consumer. As a profitable, hypergrowth startup on the path to an IPO, our standards are high, our team is scrappy, and our commitment is to execute the best work of our lives. This is YOUR CHANCE to shape the backbone of a company that's scaling rapidly and innovating boldly. As our Senior Fullstack Engineer, you'll partner with the CTO, founders, and executives to build and scale our mortgage technology platform, shipping features end to end across a mix of microservices and monolith architectures, with a focus on backend systems and third-party integrations. If you thrive in complexity, entrepreneurial problem-solving, and believe in scaling through tech and AI, this is your PLACE. Who Develops You: CTO What You're Great At: You are a seasoned engineer with 7+ years building and running production web applications, and you take a problem from a vague description to a shipped, monitored solution. You go deep on Ruby on Rails, including API-only services, ActiveRecord, PostgreSQL, background jobs, and RSpec. You're also comfortable shipping polished UI with React and TypeScript, and you've worked with GraphQL (ideally Apollo) on both server and client. You've built distributed, event-driven systems and know how to debug failures that span services, using retries, idempotency, and eventual consistency. You've also tamed third-party integrations (REST, SOAP, webhooks) and partner APIs that are slow, inconsistent, or poorly documented. You treat sensitive personal and financial data with care and have strong instincts for security and multi-tenant data isolation. You use AI and agentic coding tools at an advanced level every day, can describe how you structure context for agents and verify what they produce, and you build tooling that makes other engineers more effective. You communicate clearly: you can write a strong design doc, explain a production incident to a customer success manager, and disagree productively with a product manager. You own production through on-call, incident response, observability, and blameless postmortems. Bonus points if you have experience in mortgage tech or a similar regulated, integration-heavy domain (fintech, lending, insurance, payments, healthcare), familiarity with LOS platforms (Encompass, MortgageBot, Byte) or MISMO standards, Node.js/TypeScript services, Elasticsearch, Redis, Docker, AWS, CI/CD, saga or workflow orchestration patterns, or a history of mentoring engineers and leading cross-team projects. What You'll Do: • Design, build, and maintain features across Rails API services, TypeScript/Node services, a GraphQL gateway, and React frontends • Own integrations with external platforms (LOS systems, mortgage insurance providers, document and e-sign vendors), including data mapping, sync and reconciliation, retries, and idempotency • Design and evolve asynchronous, multi-step workflows using message queues (RabbitMQ, SNS/SQS), Sidekiq background jobs, and saga-style orchestration • Keep our multi-tenant platform correct and secure, respecting partner boundaries in every query and event • Lead technical design for significant features by writing design docs and architecture decision records, weighing trade-offs, and building alignment before you build • Identify and pay down technical debt, improving service boundaries, module design, test coverage, and developer experience • Hold a high bar in code review and help set engineering standards across the team • Join the on-call rotation, lead incident response, and follow through on root-cause fixes that prevent recurrence • Use observability tools and CI/CD to keep the platform healthy, and improve them where they fall short • Work directly with Customer Support & Success on lender-reported escalations, reproducing issues, investigating sync problems with external LOSs, and explaining findings clearly to non-engineers • Partner with Product Managers to refine requirements, uncover edge cases early, and propose simpler alternatives • Work with UI/UX Designers to turn designs into polished, accessible interfaces, and push back constructively when technical constraints affect the experience • Mentor other engineers through pairing, code review, and design feedback, including on effective AI-assisted workflows • Lead on AI-assisted engineering by using agentic coding tools (Claude Code, Cursor, Codex) daily to plan, implement, test, debug, and review, and by delegating well-scoped work to agents and reviewing their output rigorously • Build and maintain shared AI tooling for the team, including agent instruction files (CLAUDE.md/AGENTS.md), reusable skills and prompts, MCP servers connecting agents to internal systems, and automated workflows • Set and follow guardrails for AI use: verify agent output, never expose secrets or customer data, and know when a task needs a human-written solution Why Maxwell: We believe people do their best work when they're trusted, supported, and surrounded by others who are equally driven. That's why this role includes a "work from the place you work best" approach – at home, in an office, or on the move. Our competitive benefits include PTO as needed, comprehensive insurance coverage, a 401(k) match, stock option grants, and a stock purchase plan. Every team member is an owner, building the place they are proud to call "my company."