Question

can \ser\ and \estar\ be used interchangeably?
yes, since they both mean the same thing (\to be\).
no. both of them mean \to be\, but are used differently.

Explanation:

In Spanish, "ser" and "estar" both translate to "to be" in English. However, they have distinct usages. "Ser" is used for permanent or inherent characteristics (e.g., "Soy alto" - I am tall). "Estar" is used for temporary states or locations (e.g., "Estoy en casa" - I am at home). So, they cannot be used interchangeably.

Answer:

No. Both of them mean "to be", but are used differently.