Fullstack Engineer (Backend-Heavy)

Why join us? Handoff is the AI agent that runs a construction company. We help remodelers automate estimating, streamline operations, and win more work - backed by real-time cost data, intuitive design, and workflows that “speak contractor.” With over 10,000 monthly active users and $6B in annualized project volume already flowing through our platform, we’re becoming the trusted partner for the people who build our homes. We are backed by $25M+ raised from Y Combinator, Initialized, and Greycroft. Our team is distributed across hubs in Austin, São Paulo, and Buenos Aires, and we are deeply focused on building intuitive, high-impact solutions that make a real difference for our users. Senior Fullstack Engineer at Handoff You’ll play a pivotal role in shaping both the frontend and backend architecture of Handoff, ensuring seamless performance, scalability, and a best-in-class user experience across mobile and web. This role goes beyond coding - you’ll be deeply involved in understanding contractor workflows, using AI-powered automation to simplify processes, and driving the technical evolution of our platform. You’ll collaborate closely with design, product, and AI teams to build a high-impact, user-centric system. What you'll do

Own end-to-end technical delivery for 2-3 enterprise accounts, from pilot success criteria through production rollout and ongoing support.

Customize our core deliverables: estimates, takeoff drawings, and summary reports - to each client's templates, naming conventions, units, materials preferences, and branding.

Stand up and automate intake and delivery workflows (file transfer, custom CSV exports, API payloads) into and out of client systems.

Expose and document Handoff's API for clients to consume, and build SKU matching that maps our estimate line items to a supplier's catalog - maintaining mappings as catalogs evolve.

Assess each client's tech stack (POS/ERP systems such as Oracle), recommend a realistic integration path, and assist with connections to legacy systems, scoping what's feasible and never over-promising.

Lead weekly calibration reviews with the client's estimating team, incorporate correction notes, and drive accuracy against agreed error-rate targets, treating measurement as a core requirement, not an afterthought.

Meet delivery SLAs and provide first-line technical support and maintenance throughout the engagement.

Document account-specific configurations, assumptions, and preferences for continuity and clean handover.

About You

5+ years of software engineering experience, with a track record of shipping and operating production systems.

Full-stack comfort: proficient in Node.js, Python, and SQL, able to customize outputs, build integrations, and automate exports across the stack.

Hands-on API experience: designing, exposing, and documenting APIs, mapping data to a client's schema, and working with legacy or non-REST systems.

Strong client-facing skills: professional, responsive, and comfortable working directly in a client's channels (email, calls, Microsoft Teams) with both engineers and non-technical estimating staff.

Metrics-driven: you define quality metrics, track accuracy trends across iterations, and make progress quantifiable and defensible.

Self-contained and autonomous: you can own technical delivery for multiple accounts and navigate ambiguity, shifting requirements, and staggered timelines.

B2+ English, ensuring effective communication and documentation with US clients.

Bonus: exposure to LLM/AI applications, or familiarity with residential construction (framing, foundation, roofing, siding, interior scope) and estimating workflows.

What we offer

Competitive salary in USD

Attractive stock options

Unlimited PTO

Relocation allowance

Top-notch equipment

Team offsites around the world!

If you want to be the engineer customers trust to make AI work in the real world, and watch your work reshape how construction gets done, we'd love to hear from you!

Please note that we will only consider applications submitted in English.