Founding Engineer - Infrastructure

Mason - Accelerating development of the built world

Mason is on a mission to accelerate the development of the built world. We are tackling some of the most pressing challenges of our time - housing shortages, energy constraints, and decaying infrastructure - all of which are exacerbated by the slow pace of physical development.

This is one of the largest, least-modernized markets in the world. Trillions in spending, and much of the work still runs on spreadsheets, documents, and manual processes.

We create AI systems that transform some of the largest firms in the world.

A core part of this work is building the company brain: turning decades of fragmented documents, databases, emails, and operational knowledge into connected data and context that AI agents can actually use.

We're growing fast - we have an 8-figure pipeline of projects and are looking for great engineers to join our team.

Our founding team comprises a repeat founder who exited to a Fortune 500, a former tech lead at Meta Superintelligence who co-created Meta AI, and a development director who built $2B+ of projects.

This role will very quickly become Head of Engineering.

The Role

You'll be the person who makes sure our systems are enterprise-grade, secure, and built to scale. You'll design and build the backend and infrastructure that power Mason's company brain and the AI agents working on top of it.

We need someone who thinks carefully about how distributed systems communicate, how data moves through a platform, and how to make long-running workflows reliable. You'll own architecture and implementation, then make sure what you build holds up in real customer environments.

You'll work closely with our CTO and Deployment engineers. Data pipelines, storage, and processing are part of this role. You'll bring particular depth in the architecture, execution, and operational reliability of the overall system.

What you'll build

• Secure, multi-tenant infrastructure and backend services for enterprise customers
• System architecture for agent-based workflows running in sandboxed environments, including state, queues, retries, and recovery
• Shared data infrastructure for ingesting and processing large document collections and structured datasets
• Storage, indexing, and APIs that make company knowledge accessible to agents and applications
• Distributed systems designed for correctness, performance, observability, and cost as workloads grow
• CI/CD, monitoring, and deployment automation that make new customer environments repeatable and easier to operate
• Internal tooling that lets a very small team ship extremely fast

Tech stack and tools

Relevant experience includes:

• Languages and backend: Python, TypeScript, Node.js, SQL
• Data platforms and pipelines: PostgreSQL, Snowflake, Databricks, AWS, dbt
• AI and agents: Anthropic and OpenAI APIs, Claude Agent SDK, Vercel AI SDK, LangGraph, MCP
• Retrieval and memory: pgvector, Cohere, Hindsight, RAG pipelines
• Workflows and compute: Inngest, Temporal, Blaxel, Modal
• Cloud and infrastructure: AWS, Docker, Kubernetes, Terraform

We value experience building production systems with these or comparable technologies.

What we're looking for

• At least four years of software engineering experience, with substantial ownership of production backend or infrastructure systems
• Deep experience with system design, distributed systems, databases, and architecture
• A track record building and operating reliable software that other engineers or enterprise customers depend on
• Comfort owning cloud infrastructure, deployment, security, and production troubleshooting
• Strong software fundamentals and the judgment to choose simple designs that can grow with the product
• High ownership and high agency: you take responsibility for the system after it ships
• Experience with large data workloads or production AI agents is a strong plus
• A fast learner who actively adopts useful tools and can turn ambiguous requirements into working software

Team and culture

• CEO is a second-time founder who sold his last company to Coinbase
• CTO was previously a tech lead at Meta Superintelligence and co-created Meta AI
• COO has led over $2B in real estate development
• Backed by investors, operators, and major development firms
• Working directly with teams managing billions in AUM
• Small, intense, low-ego team with substantial ownership from day one
• Regular board game nights, lots of laughs, no corporate nonsense

If you want to help redefine the built world - let's talk :)