San Francisco-based residential real estate technology company Mainstay has raised more than $18 million in growth capital and acquired Truelist, an AI-powered listing platform built for brokers and agents.

The funding brings together new investors including Parker89, Stackpoint, Alpaca VC, and FJ Labs, alongside existing backers Khosla Ventures, Era Ventures, and Clocktower Technology Ventures.

Mainstay will use the capital to expand beyond the largest residential real estate investors and bring its data, pricing intelligence, and automation infrastructure to brokerages, agents, and smaller investors.

Building an AI infrastructure layer for residential real estate

Mainstay describes itself as an intelligent system of record for residential real estate, connecting data, decisions, and execution throughout the property lifecycle.

Its platform combines customer data, proprietary information, and thousands of external sources into a continuously updated record for individual properties. Its agentic platform then turns those insights into actions across workflows such as transactions, property taxes, HOA management, and payments.

The system is designed to continuously generate outcome data from executed actions, which can then improve future decisions.

Scaling across the real estate ecosystem

Mainstay says it has facilitated more than $12 billion in real estate transactions and executed over 2 million agentic workflows across more than 50,000 external portals. The company serves 95% of the 60 largest residential real estate investors.

The company was carved out of Opendoor as an independent business in August 2024 after its founding team spent more than a decade building residential real estate technology at scale.

CEO and co-founder Dod Fraser, former President of Opendoor, leads the company alongside President J.D. Rasmussen and COO Michael Dulfer.

Truelist expands the platform to brokers and agents

Truelist helps brokers and agents create, manage, and distribute property listings. Its technology is being integrated with Mainstay's data, pricing intelligence, and automation capabilities.

Truelist founder and CEO Carey Armstrong will join Mainstay as Chief Strategy Officer. Armstrong previously served as Vice President of Premier Agent at Zillow and co-founded and served as COO of Tomo.

The acquisition gives Mainstay an entry point into brokerages and agent workflows while adding a listing data layer to its existing infrastructure.

Mainstay plans to use the new capital and acquisition to expand its platform across more of the residential real estate market, from individual investors and agents to large institutional operators.