kotlinx-datetime으로 날짜 다루기

The core stdlib has no shared date type, so KMP uses kotlinx-datetime, an official multiplatform library for time.

You pull kotlinx-datetime into commonMain in your build file, and then every target can work with dates the same way.

An Instant is a single point on the timeline, the same exact moment no matter which device reads it.

The same instant looks different per TimeZone. The library lets you convert moments into local wall-clock time safely.

A LocalDateTime is the human-readable date and time, like a calendar entry, without any time-zone baggage attached.

From a LocalDateTime you can read fields like year, month, day and hour, all in plain common Kotlin.

When you only care about the day, use LocalDate. It models a date with no time component at all.

You can add or subtract a Duration from an Instant to shift moments forward or backward in time.

kotlinx-datetime can parse ISO strings into instants and turn them back into text, ideal for API payloads.

Because the library is multiplatform, your date logic produces the same result on Android, iOS and desktop. 🙂

Put all your time handling in commonMain with kotlinx-datetime, so the two apps never disagree about dates.

Use kotlinx-datetime for dates: Instant for moments, LocalDateTime for people, and shared code that agrees across platforms.