If you&#x27;ve got a strong track record and connections then you can raise money with just an idea, but in reality most founders don&#x27;t have that so the only way they can prove their ability is via their actions and these days that tends to mean at least building something to prove what you&#x27;re capable of.<p>BTW. Andy Bechtolsheim invested in Google three years after they&#x27;d started working on it (as part of their Phd), they&#x27;d already launched a public version (google.stanford.edu) with real users by the time he invested. Justin Kan had been working on Kiko for a year before YC invested. Alexis &amp; Steve had been working on MyMobileMenu for a year before they pitched it to YC and PG convinced them to pivot.<p>It&#x27;s easy to romanticizes away the slog of work that goes in before a startup raises money, but many successful founders had years of work before they raised seed funding.