Mainstay, a San Francisco-based provider of an intelligent system of record for residential real estate, has raised over $18 million in funding. Backers included Parker89, Stackpoint, Alpaca VC, FJ Labs, Khosla Ventures, Era Ventures, and Clocktower Technology Ventures. The company will use the funds to expand operations and development efforts. Led by chief executive officer Dod Fraser, Mainstay provides an agentic platform connecting data, decisions, and execution across the residential asset lifecycle. The solution combines proprietary and external data sources into a single record for every property, using agentic automation to handle workflows across transaction execution, property taxes, HOA management, and payments.