How to Build an Emoji Keyboard: Input Methods and IME Integration
An emoji keyboard is a grid of buttons on top of a deep stack of input method APIs, grapheme handling, and recency tracking. Here is the component map. Building an emoji keyboard is a surprisingly deep exercise. On the surface it looks like a grid of buttons, but underneath it touches input method frameworks, surrogate pair handling, recency tracking, skin tone selection, and platform-specific insertion APIs. I built one for a chat client and hit every one of these. Here is a map of the components and the decisions that matter. The project started as a simple grid of emoji buttons and took six weeks to get right. The grid was done in two days. The remaining time was spent on search, skin tone selection, recency tracking, platform compatibility, and accessibility. The emoji keyboard was more complex than the chat client itself. The Data Layer Every emoji keyboard starts with a dataset. The canonical source is the Unicode CLDR emoji annotations, which provide a canonical name, keywords, and a category for each emoji. You can use a packaged library like emoji-mart or emojibase, or you can load the CLDR data directly. The tradeoff is bundle size versus freshness. A packaged library is larger but includes search index and category metadata. Loading CLDR raw is smaller but requires you to build the search index yourself. The dataset must include sequences, not just single code points.