“I pushed out a tweet and basically said I'm going to build an open source alternative to Docsend and it went just like crazy within a couple hours it got like 40,000 views lots of people mentioned that they would love to see this as an open source project so over the weekend I actually built it.”

Single tweet got 40K views validating open-source Docsend before any code

Mark used a single tweet as a demand test before investing real engineering time. The 40K-view response and explicit enthusiast replies confirmed both the problem and the open-source angle, removing guesswork from the build and giving him the conviction to sprint a weekend MVP.