U+1F602 · emoji since 2010
Officially called face with tears of joy, this is the one you send when something is so funny you're laughing until you cry. For years it has been one of the most used emoji on the planet.
It's the go-to reaction to a good joke, a clumsy fail, or a meme that got you. Some younger users have drifted to 💀 for the same feeling, but 😂 is still the universal shorthand for that is hilarious.