We built a message editor at Intercom twice because the first attempt using ContentEditable proved to be more complex than expected, with issues such as inconsistent rendering on all devices and unexpected behavior. After realizing this, we adopted a new approach called the Block Object Model (BOM), which gave us complete control over the editing experience and enabled us to build a solid editor that supports features like lists, formatting, images, and videos, ultimately leading to a better product for our customers.