As an engineer, I just prefer everything as code, instead of drag and drop, config and etc. So a few years back, I've created a project on GitHub, trying to make it work: to compose a responsive design newsletter email with a custom markup language. Finally got some time to implement it and publish it. Note: this project only generates an HTML email, without any function such as managing subscribers or sending emails. As there are plenty of solutions offering those. SLM (aka the English word slim) = Super Lightweight Markup. Isn't it sexy? 🤓 And for the tag delimiter, I've chosen ⇥⇤, which is rarely used in text content, it means slim as well, just imagine: ⇥)(⇤ it's so vivid!