If you're looking for a headless documentation platform with AI-powered semantic search and bi-directional Git sync, GitBook is an excellent choice. It integrates seamlessly with GitHub and GitLab, allowing for Docs-as-Code editing and management within your codebase. GitBook's AI-powered search and branch-based workflow ensure your documentation stays in sync with your code, and offers various collaboration tools with features like inline comments and threaded discussions.
Another robust option is Document360, an AI-powered knowledge base tool designed for technical writers, product owners, and customer support teams. It offers advanced features like powerful search, rich analytics, and AI-powered suggestions to automate documentation processes. Document360 integrates with over 120 tools and provides a customizable knowledge base site with an embeddable widget, making it a versatile tool for managing and sharing knowledge efficiently.