Founders who've already built a product haven't missed the 'validation' window. The focus simply shifts from 'is there a problem?' to de-risking subsequent assumptions: Is the solution worthwhile? Will people pay enough? Can customers be acquired profitably? This process is ongoing, even at scale.

Instead of a functional prototype, Mirror's founder raised a seed round with a "smoke and mirrors" version: an animated video behind one-way glass. This focused on selling the *feeling* and brand experience to investors, proving demand before spending capital on complex engineering.

Validate business ideas by creating a fake prototype or wireframe and selling it to customers first. This confirms demand and secures revenue before you invest time and money into development, which the speaker identifies as the hardest part of validation.

Sure's journey shows that PMF is not binary. The company achieved initial PMF with its prototype, then again with its first product, and again after its pivot. However, launching auto insurance with a major EV brand created a "literal rocket ship" moment that represented a completely different order of magnitude of PMF.

To de-risk their unconventional idea, Liquid Death created a fake ad and a Facebook page to test market reception. They secured millions of views and 80,000 followers, proving demand and generating traction that was crucial for raising capital, turning a concept into an investable business.

Instead of waiting for a working product, the founders invested in a conference booth with just screenshots. This early, public validation test, though risky, attracted two crucial prospects who became their first customers. This demonstrated market demand before the product was fully built, a move many founders would avoid.

Instead of immediately hiring after validating his idea, the founder of Sure worked alone for a year. He used this time to secure the company's first critical insurance partner, ensuring the business was on stable footing before asking anyone else to leave their job and join the venture.

Crisp.ai's founder advocates for selling a product before it's built. His team secured over $100,000 from 30 customers using only a Figma sketch. This approach provides the strongest form of market validation, proving customer demand and significantly strengthening a startup's position when fundraising with VCs.