Static vs Const Variables

Use const by default. Use static when you need a 'static reference or shared global state (e.g. static LOGGER: OnceLock<Logger>).

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const: compile-time constant. Inlined at every use site. No fixed memory address.

const MAX: u32 = 100;

static: single instance with a fixed memory address for the program’s lifetime. Can be referenced (&'static).

static GREETING: &str = "hello";

static mut: mutable static — requires unsafe to access.

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Key differences:

	const	static
Memory address	No (inlined)	Yes (one location)
'static reference	No	Yes
Mutable	No	Yes (unsafe)
Interior mutability	No	Yes (Mutex, OnceLock, etc.)