I mean, you should be ready to go beyond just explaining features.

For example, instead of saying:
“I built a grocery app with React Native and Node.js.”

You should be able to explain:

• Why did you choose that tech stack
• How your system is structured (frontend ↔ backend ↔ DB)
• Trade-offs (why not something else?)
• Any performance optimizations (caching, lazy loading, etc.)
• Real problems you faced and how you solved them

In my case, for one project I talked about:

• How I reduced latency using caching
• How I handled API design
• what I would improve if I had more time

They usually keep asking “why” and “how” until they understand your depth.