---
title: 'Founding AI Engineer at Mason AI'
canonical: 'https://feeny.ai/job/founding-ai-engineer-mason-ai-san-francisco-zr440vpx5q7s'
type: 'job'
last_seen: '2026-09-10'
---

# Founding AI Engineer at Mason AI

- **Company:** Mason AI
- **Location:** San Francisco, CA
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-03-19
- **Last confirmed live:** 2026-09-10
- **Apply:** https://jobs.gem.com/mason/am9icG9zdDrbO9dq8Uy4Y_wwmKVh217K

## Job description

Mason AI is on the frontier of agentic AI for the built world: we're the technical leaders at building AI that checks blueprints are buildable and safe.

We’re looking for a Founding AI/ML Engineer to help us scale what works for residential projects in California to all construction across the country.

You will go deep on the cutting edge of optimizing multimodal AI agents; you will hillclimb on computer vision evals; and you will run time-boxed experiments that are high-risk, high-reward. You will become a domain expert on the ADA, Wildland-Urban Interfaces, and other wonky parts of the building code. Your work will directly affect the built environment of California within the first month of joining.

You will have a massive impact on the product, the company's future, and the country's, as we accelerate American construction. Join us.

## Who you are

- Either a SWE passionate about growing as an ML/AI Engineer, or a ML Engineer who's fast at prototyping.
- You can run experiments quickly and develop research taste.
- You're mission-oriented and looking for your life's work. You care about America's ability to build.
- You love ownership and don't mind ambiguity or unblocking yourself.
- You have the curiosity of a policy wonk to digest building codes and architectural diagrams.

## What you'll do

- 60+% of your time will be spent improving the accuracy of our multimodal agents that check blueprints for building code compliance. This can range from building autoresearch to improving our evals to running sweeps on new experimental features you build. Your research taste will direct this work.
- Talk to users and dogfood the product weekly
- Wear hats as needed on topics ranging from running computer vision experiments, lightweight data engineering, building internal tooling, improving the webapp, and more.

Our operating principles

- Fail fast and cheap. Slugging percentage matters more than batting average.
- We can make a lot of mistakes as long as we get a few things right.
- A written culture - we document our thinking on the few things that matter most.
- Internal tooling is a first-class use of time.
- In-person work is a must.

## Benefits

- Competitive salary ($160k-$210k).
- Generous early-stage equity (0.75%-2%).
- Free lunch and dinner (ordered at 6 pm) at the office.
- Fully paid health insurance with over $1000/year in employer contributions to an HSA.
- A 401(k) that accepts pre-tax and Roth contributions.
- A commuter benefits account and a monthly wellness benefit.
- Opportunity to shape the future of our country.

Interview process

Our interview process aims to be lightweight and respect candidates' time. We expect it to take 2 weeks or less.

- Intro call (30 min) - Informal chat on your interests and experience
- AI Coding & Culture interviews (90 min)- Designed to mirror real work you'd do at Mason, you'll build a prototype for a slice of our product. AI coding tools (e.g. claude code, conductor, wisprflow) are strongly encouraged.
- Learn more about how you've navigated challenges in (or outside) of work.
- Paid work trial (3 days) - We'll set you up to run evals for our multimodal agent on our repo, and we'll ask you to generate hypotheses for experiments to run, run those experiments, and then analyze them. You'll be evaluated on your speed at running thoughtful experiments. We're flexible on scheduling, and usually run these over the weekend to minimize impact on your weekday schedule.
- Full-time offer 🎉

## About Mason AI

## Company Overview
- **One-liner**: Mason AI automatically reviews residential building plans against building codes, drafting first-pass comment letters so human reviewers can finish plan reviews up to 40% faster.
- **Entity Type**: Private (Seed stage)
- **Headquarters**: San Francisco, California, United States
- **Founded**: 2025 (based on timeline)
- **Founders**: Salim Damerdji (CEO) and Alex (CTO)

## Core Business
- Primary industry/industries: Construction technology (ConTech), Artificial Intelligence
- Target customers: Private plan review firms, building departments, and architectural firms (B2B)
- Mission or purpose: To make it effortless to draft code-compliant blueprints and unlock housing abundance in America by automating the most tedious parts of plan review.

## Products & Services
- **Mason AI Platform**: An AI-powered plan review tool that ingests permit sets (blueprints), checks them against building codes (CRC, CPC, CEC, CMC, CalGreen, CWUIC, and Energy Codes), and pre-populates a draft comment letter. It uses a proprietary computer vision model (97% accuracy on floorplan elements) and an agentic architecture to handle the physical-world complexity of blueprints.

## Market Standing
- **Valuation/Market Cap**: Not disclosed
- **Key Metric**: Raised $4.3 million in an oversubscribed seed round (March 2026)
- **Notable Investors/Partners**: Lead investor: Urban Innovation Fund (Julie Lein). Angel investors include Zack Rosen (Pantheon, CA YIMBY), Brian McClendon (co-creator of Google Earth & Google Maps), Rose Bloomin (Plurality Institute), Adam Cohen (VP of Eng @ Instacart), David Bloomin (SoftMax), and Steve Bartel (CEO @ Gem).
- **Growth Signals**: 96% expert agreement rate on code checks; customers report saving multiple hours per review (40-60% faster); hundreds of cities already using the platform; planning to expand to multifamily, commercial, and mixed-use projects by end of year.

## Competitive Advantages
- **Proprietary computer vision model** built specifically for blueprints, achieving 97% element-level accuracy in reading walls, doors, windows, fixtures, etc.
- **Domain-specific context engineering** framework informed by manual review of hundreds of blueprints, optimized to handle the massive context of detailed plans.
- **Fully agentic architecture** designed to compound improvements with future model upgrades, unlike simpler RAG-based competitors.
- **Continuous evaluation culture**: Half of engineering time goes to tests and synthetic edge cases; tracks even a one-inch drift in segmentation.
- **Code currency**: Updates automatically with every new code cycle (2022, 2025, etc.), so reviewers never work from a stale mental model.
- **Designed for human oversight**: No comment is added to a response letter without a professional reviewing Mason’s reasoning.

## Strategic Focus
- **Expand project types**: Plan to review multifamily, commercial, and mixed-use projects nationwide by end of 2026.
- **Embed into CAD tools**: Build direct integrations into the CAD tools architects use, making code-compliance checking instantaneous during the design phase.
- **Hire founding team**: Actively recruiting founding engineers, a founding GTM lead, and an in-house principal plan reviewer to scale the product and go-to-market.

## Why Work Here
- **Culture**: Small, fully technical, in-person team in San Francisco. The CEO describes the team as “relentlessly focused” and born out of “a shared passion for unlocking housing abundance in America.” High ownership and low bureaucracy.
- **Remote/Hybrid/Office**: In-person work is a must for most roles (San Francisco office). One role (In-House Chief Building Official) is listed as remote.
- **Engineering culture**: Heavy emphasis on evals, testing, and shipping. The founding AI engineer (Francie McQuarrie) is “happiest at the seam between a statistical model and the people who have to act on it.” Half of engineering time goes to tests and synthetic edge cases — “accuracy is our core product.”
- **Impact**: Opportunity to solve a decades-old research problem — automatically checking blueprints against building codes — and to directly address America’s housing shortage.

## Sources
1. [withmason.ai](https://www.withmason.ai/)
2. [withmason.ai/careers](https://www.withmason.ai/careers)
3. [withmason.ai/about](https://www.withmason.ai/about)
4. [jobs.gem.com](https://jobs.gem.com/mason)
5. [withmason.ai/blog](https://www.withmason.ai/blog/announcing-our-seed-round)

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