We had an idea that we wanted to build a particular type of B2B SaaS product, that solves a problem really well, for large companies in markets that are overlooked.
We heard about a problem, that we could solve, and called one of the dozen companies in the market. We asked them about how they handle solving the problem today, and gave them our vision of the future. We worked with them to develop a business case.
They signed a contract.
Then we started to write the code.
For my latest startup, a Saas product for software engineering teams, we went to the 10 largest customers we could possibly get using our product. We explained them the problem they're likely facing and the solution we came up with.
All showed interest, but when two decided to sign a contract in order for us to provide this solution, we knew we had validated our idea.
The main thing with validation is that many will show interest, but it's when they pull out their checkbook that really counts.