Before you can evaluate whether a deal makes sense, you need to know what similar properties are actually selling for. Redfin gives you fast access to comparable sales, price history, and days-on-market data — the baseline numbers behind any offer.

It also surfaces flood risk data directly on individual listings, which is a useful second data point alongside FEMA's official flood maps (more on that below).

If you're evaluating a buy-and-hold or BRRRR deal, your numbers are only as good as your rent estimate. RentCast pulls rental market data by address, giving you a fast, defensible starting point for projecting income — rather than guessing based on a listing you saw down the street.

Flood zone designation affects everything from insurance costs to long-term resale value, and it's easy to overlook during a fast-moving deal. FEMA's Flood Map Service Center is the official source — plug in an address and get the property's actual flood zone designation, straight from the source insurers and lenders rely on.

Once you're past due diligence and into planning a renovation, accurate measurements matter. CubiCasa lets you generate a professional floor plan from your phone in minutes, which is useful for rehab budgeting, contractor scopes of work, and listing prep once the project is done.

A great deal can still go sideways with the wrong contractor. Before you sign anything, a quick BBB search shows you complaint history, accreditation status, and how a business responds when things go wrong — information that's easy to skip when you're excited about a project, but expensive to ignore.

These five are a starting point. We've put together a complete, organized collection of the tools our borrowers use most — covering property research, due diligence, rehab planning, deal calculators, contractor vetting, and getting your LLC set up in Wisconsin.