Market validation stands for analyzing if your idea for a product is a good idea and that there’s a need in the market.
It’s an umbrella term for the key figures supporting the validation of your idea. When presenting your product, you will have to list up different metrics, such as survey & interview results or numbers of theoretical purchases. Since in this phase you don’t actually have the product yet, you are just mapping the market demand to find validation for your idea.
For example, you can create a marketing campaign and measure how many people click on the link. Of course, since you don’t have the product just yet, you can navigate the link to a landing page informing the customer that the product is not available yet.