Markwhen

Markwhen is a specialized markup language and toolset that transforms plain text with date annotations into visual timelines and calendars. You write events using a simple, markdown-like syntax where dates are naturally incorporated into the text, and the system automatically converts them into structured timelines, Gantt charts, or calendar views. The syntax supports various date formats, ranges, recurring events, timezones, tags, groups, and custom properties, making it flexible for different types of time-based documentation.

The tool includes multiple components: the core Markwhen language parser, the Meridiem web editor for collaborative editing, and integrations with popular tools like VS Code and Obsidian. What sets Markwhen apart is its focus on plain text as the source of truth - you maintain your events in an easy-to-read text format while getting the benefits of visual representations. The system outputs structured JSON data alongside the visual timelines, allowing for further processing or integration with other tools.

Markwhen works best for technical users who prefer text-based workflows but need visual timeline representations. It's particularly useful for project managers tracking milestones, developers documenting project timelines, writers maintaining journals or blogs with chronological entries, and teams collaborating on event planning. The plain text format makes it version-control friendly and easy to integrate into existing documentation workflows.