Who hurts
Landlords with 5–50 units, property managers, and eventually homeowners.
The problem
Repair history lives in a filing cabinet and one person's memory. New managers re-diagnose solved problems, warranties expire unclaimed, and the same contractor is hired twice for the same failure.
What you build
A per-property timeline: photos, invoices, parts, warranty expiry and contractor. Contractors log jobs free to get discovered; owners pay for the record and the handover pack when the property sells.
Why now
Nobody has built the boring version of this well, and the sale-time handover gives it a moment where the value is obvious and urgent.
Validate it this week
Digitise one property manager's last two years of paperwork by hand. Ask what they'd pay to never lose it again.
Why you'd keep winning
The record itself. History accrues, is property-linked rather than owner-linked, and transfers on sale — which is the flywheel.
The honest risk
Classic cold-start. Solve the landlord side alone first and treat the contractor network as a later chapter, not a launch requirement.
The prompt is written to make an AI argue with you before it writes code — that first round of pushback is worth more than the scaffold.