Design
Why the same emoji looks different on every platform
Unicode defines the character and its meaning. It does not define a single drawing. Each vendor creates its own artwork, so the same sequence can have a different personality on each platform.
One character, many drawings
The code point tells the system which emoji to show. The font supplies the shape, color and detail. Apple, Google, Microsoft and other vendors each maintain their own designs.
Open artwork sets
Noto, Twemoji and OpenMoji are open artwork sets with different visual styles. EmojiBase shows them side by side so you can compare details before choosing an image for a design.
Licenses matter
Noto is available under Apache 2.0, Twemoji under CC BY 4.0 and OpenMoji under CC BY-SA 4.0. Check the license before redistributing artwork in a product or template.
Text is not an image
A raw emoji character will use the reader platform font. If the exact artwork matters, use an image and provide alternative text. If the meaning matters more than the drawing, the character is usually the better choice.