49.7 million
U.S. rental unitsIn 19.0 million rental properties. U.S. Census Bureau, Rental Housing Finance Survey 2024, reference year 2023; excludes public and transient housing.
Company
Rental housing runs on coordination.
DoorStopper is building the AI-assisted operating software for it: for property managers and the rental portfolios they run, starting with independent property-management companies, one workflow at a time.
The work around the lease is large, repetitive and spread across tools.
A rental property is a small operating business. Its year is decided by a handful of moments: a lease-up, a turn, a missed payment, a property owner’s question. Each one crosses a property-management system, listing channels, a screening vendor, inboxes and spreadsheets, and a person carries it from one to the next. AI can now prepare much of that work: the listing, the update, the file, the reminder. Making it part of how a company actually runs is the harder step, and the one DoorStopper is building for, with people approving what goes out and deciding what matters.
A large base of repeated work.
79,466
Residential property-manager establishmentsPrivate establishments, NAICS 531311, 2025 annual average. U.S. Bureau of Labor Statistics, QCEW. Counts worksites, not companies.
58%
Of surveyed property-management companies using AIUp from 20% a year earlier; 8% had automated any workflow end to end. Buildium and NARPM, 2026 industry report, 1,060 property managers surveyed May 2025. Vendor-sponsored survey.
National context, not a count of DoorStopper customers. Who manages each property, and how many independent property-management companies there are, is not published in these sources.
AI use is rising. Changing how the work runs is the harder step.
In a vendor-sponsored survey of 1,060 property managers (Buildium and NARPM, surveyed May 2025), AI use rose from 20% to 58% in a year, while 8% had automated any workflow end to end. Leading property-management systems are adding AI and workflow tools inside their own products. Independent managers who run other systems, or several, still coordinate turns, exceptions and owner updates across tools. That gap between trying AI and running work through it is where DoorStopper starts.
Independent property managers, one conversation at a time.
The first customers are independent and regional property-management companies that manage rentals for third-party owners, along with owner-operators who run their own portfolios with their own team. Distribution today is founder-led: a free portfolio review, then one scoped workflow under a written proposal. Prices are published. DoorStopper Protect, the rent-risk workflow, is one of the first we expect to offer, with financial protection only through a licensed provider once a program is approved; turns and owner reporting are the others.
Prepare, approve, record.
The software, in development, prepares the next step from the record, routes it to the person who decides, and records what happened. It works beside the property-management system, which stays the system of record for leases and the ledger. Nothing is published, sent or submitted without a person approving it. Licensed roles stay where they are: the manager’s team performs leasing acts and decides applications, and a licensed provider decides any coverage.
See two journeys, step by stepFrom one workflow to the operating work of the portfolio.
An expansion hypothesis, to be proven with customers.
- 01
One paid workflow
A property-management company starts with the workflow that costs it most: turns, missed payments or owner reporting.
- 02
Repeatable deployment
The same workflow deploys from a PMS export at the next company, with less custom work each time.
- 03
Broader use inside the account
The second and third workflows share the same schedule, records and owner updates as the first.
- 04
More of the work in one place
More of the portfolio’s operating work runs through DoorStopper, and the account’s configuration, history and connections deepen.
What is in place, and what is still to prove.
An operating history in leasing (below); published prices; the product designed end to end, with two journeys and the approval model; the first workflows in development.
Paying platform customers; how fast a workflow deploys from an export; retention and expansion inside an account; an approved provider program for Protect.
We started where the work begins: an empty unit.
From April to June 2026, DoorStopper ran a tenant-placement service for individual landlords, with licensed brokerage partners, on leasing tools we built ourselves: listing drafts from one property form, one listing prepared for thirteen rental platforms, and an inquiry inbox whose drafted replies were screened by a fair-housing filter and held for a person to approve. The service made eight placements. We closed that landlord service in June 2026 to build for property-management companies.
Read the full operating historyInquiry reply · review2026 placement tools
Inquiry by SMS“Is the two-bedroom still available? It would be me and my two kids.”
Drafted reply
Yes, it’s available. It’s a quiet building that suits adults best.
Fair-housing filter held this replySteering by familial status, a protected class. Suggested: “Yes, it’s available. Would you like to see it this week?” Nothing sends until a person approves it.
Historical capability, reconstructed for illustration.
Kelvin Tran, founder.
Kelvin founded DoorStopper in April 2026 and ran its placement operation, with licensed brokerage partners, from listing to lease. Before DoorStopper, he founded and ran Solisa AI, software for insurance brokerages (2024 to 2026); Solisa AI, not DoorStopper, reached $2.4M ARR at peak. Stanford GSB, MBA, completed.
Two ways in.
Start with a free portfolio review.
Talk about your portfolioWrite to kelvin@doorstopper.io with “Investor” in the subject line.
Email Kelvin