Senior Full Stack Engineer - Seattle

About

Haus is the incrementality platform leading brands trust to optimize billions in ad spend worldwide. Using frontier causal inference-based econometric models to run experiments, we help brands measure the business impact of marketing, pricing, and promotions with scientific precision.

Role

You’ll build and evolve the systems that power how the world’s leading brands understand the true impact of their marketing spend. Our platform runs geo-based experiments, integrates with major ad platforms (Meta, Google, TikTok), and delivers causal inference results that directly drive budget decisions worth millions of dollars. This is a full stack role where you’ll work across a Python/Flask API, a React frontend, and the data pipelines and integrations that connect them. You'll hit the ground running on a production system with real customers, shipping work that compounds in impact over time.

What You’ll Do

• Own features end-to-end: from API design and database migrations through React UI and data visualization, all the way to monitoring and on-call support
• Build and harden integrations with third-party ad platforms (Meta, Google, TikTok) — design for reliability across APIs you don’t control
• Evolve and modernize a production Flask + React application that serves hundreds of customers — improve architecture incrementally while shipping continuously
• Design and build data-rich UIs: charts, dashboards, and interactive tools that help marketers understand complex experimental results
• Collaborate closely with scientists and data engineers to translate statistical outputs into product experiences customers can act on
• Use AI development tools as part of your daily workflow to accelerate delivery, explore solutions, and raise the ceiling on what you can ship
• Participate in on-call rotation and own the operational health of the systems you build
• Review code across the team and help set the bar for quality, clarity, and maintainability

Qualifications

• 5–10+ years of experience building and shipping production web applications and APIs
• Strong across the full stack: you can build a well-structured API endpoint, write a database migration, and implement the frontend that consumes it
• Proficiency in Python and React (or strong equivalents with willingness to ramp); experience with Flask, SQLAlchemy, or similar frameworks is a plus
• Experience working in and improving large, established codebases — you’ve navigated legacy systems, made pragmatic tradeoffs between refactoring and shipping, and left things better than you found them
• Comfort with cloud-native environments (GCP preferred): you understand how to deploy, monitor, and operate services in production
• Experience with relational databases (MySQL/PostgreSQL) and data-heavy applications
• Track record of working effectively with AI development tools (Claude, Cursor, Copilot, or similar) — you’ve integrated them into your workflow and can articulate how they change the way you build software
• Strong product sense: you think about what customers need, not just what the ticket says
• Excellent communication skills — you can explain technical tradeoffs clearly and work effectively with scientists, product managers, and other engineers

Bonus Points

• Earlier stage startup experience
• Experience with ad platform APIs (Meta Marketing API, Google Ads API)
• Experience with data visualization or experimentation platforms

We Offer

• Flexible PTO - take time when you need it!
• Equity – Startup environment with part-ownership in our successes
• Top of the line health, dental, and vision insurance - multiple plan options so you can pick what fits you best
• Free Lunch – Grab a bite on us when you choose to work from the office (hub locations include SF, NYC and Seattle)
• New Parent Leave – take time to welcome your newest Hausmate

Benefits

• Inclusive culture where everyone feels seen, heard, and empowered to contribute
• Flexible PTO
• Equity
• Health, dental, and vision insurance
• Free lunch
• New parent leave

Equal Opportunity Employer

We make hiring decisions without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, veteran status, or any other protected status. We believe diverse perspectives make us stronger and are committed to an inclusive culture where everyone feels seen, heard, and empowered to contribute.