How to Build Confidence in Junior Devs

Telling a junior developer they're doing well is nice. Telling them exactly what they did well is more useful. They can repeat it.

I'd give them a task with a clear finish, stay available, and review it while the decisions are still fresh. Let them explain the approach before offering mine. Confidence grows more steadily when someone can see the evidence of their own progress, rather than having to take a senior colleague's reassurance on trust.