すぐに

すぐに has two core meanings: immediately (time) and right there (proximity/distance).

TIME (immediately):

• すぐに来(き)てください: please come right away
• すぐに分(わ)かった: I understood immediately

PROXIMITY (nearby):

• すぐそこ: right there, very close
• 駅(えき)はすぐそばだ: the station is right nearby

VARIANT:
すぐ can be used without に with the same meaning. すぐに is slightly more emphatic.

SIMILAR EXPRESSIONS:

• 直(ただ)ちに: immediately (formal, often used in announcements and official contexts)
• 今(いま)すぐ: right now (more urgent than すぐに)
• もうすぐ: soon, shortly (indicates something is about to happen, NOT immediate)
• さっそく: promptly, without delay (implies willingness or eagerness)

COMMON MISTAKE:
もうすぐ means "soon" (in the near future), while すぐに means "immediately" (without delay). These are not interchangeable.