What’s the #1 mistake founders make in their first six months of product development?

I’ve seen a repeating pattern while working with early-stage founders: most startups don’t fail because of weak ideas, but because of weak execution, especially when it comes to their software.

One founder I worked with built their MVP in a rush. No modular architecture, no testing, and a stack that couldn’t scale. Nine months later, when investors were paying attention, the system collapsed under its own weight.

Instead of shipping features, the team was buried in bug fixes. Instead of scaling, they were patching. They didn’t run out of ideas, they ran out of time.

This made me rethink how I approach development. For me, the first six months of a build are the real make-or-break moment for a startup.

So I’m curious to hear from this community:

When you launched your first product, did you prioritize speed or scalability?

If you could go back, what would you do differently?

(P.S. I now run DevVoid.org, where I partner with founders to avoid these exact pitfalls. Always happy to connect if this resonates.)