In 2008, I struggled to raise funds for Twilio due to the global financial meltdown, and many investors dismissed our developer service idea as foolish.

We built the Twilio prototype in about four months, and early customers provided encouragement by building interesting ideas on the platform, validating our direction.

When we launched our messaging product, it quickly became a significant part of Twilio's revenue, surpassing our voice services.

After receiving positive feedback from potential customers about the Twilio API, I decided to drop everything else and focus on building it full-time.

Raising our first half a million dollars was more challenging than raising our first $200 million, as investors were skeptical about mobile voice technology at the time.

We currently have 20 paying customers and have generated about $200,000 in annual revenue, while raising a round of $1.5 million.

Launching Watsi on August 23, 2012, was initially underwhelming, but after posting on Hacker News, we quickly gained traction and funded all our medical treatments in our pipeline within hours.

We raised money for the first time after five years of existence, once we had a clear picture of our market and customer traction.

When I started talking about the Twilio idea, I noticed that developers would initially seem uninterested, but then they would ask questions about potential use cases, indicating a latent need.