Org mode vs SiYuan

Org mode is a structured plain-text format and a mode for GNU Emacs, suited to work ranging from notes and markup to literate programs. It combines task planning, time tracking, document editing and publishing. Tasks can have TODO states, priorities, deadlines, schedules and tags, with clocking and customizable agendas. Org documents use nested sections that can be folded or unfolded, and tables support formulas, references, and CSV or TSV imports. Org Babel runs source blocks in more than 80 languages. Documents can be exported to formats such as HTML, LaTeX, ODT and Markdown, and projects with multiple Org files and resources can be published. Org Capture collects structured information from Emacs and other applications, including browsers and PDF viewers. The full feature set is exclusive to GNU Emacs, though third-party file tools are listed for Android, iOS and web. Org is free, included with GNU Emacs, and also installable through package management or its Git repository. Recent releases require a recent Emacs version.

SiYuan is a personal knowledge management system for building a linked collection of notes. It supports Markdown, block-level references and bidirectional links, and organizes content into blocks with more than 20 block-level and more than 10 span-level element types. Backlinks can be filtered and searched; relationship graphs are available across a notebook and at block level. Databases support relations, rollups and templates, while flashcards use the FSRS spaced-repetition algorithm. Its AI feature connects to OpenAI for writing continuation, translation, summaries, brainstorming and grammar or spelling corrections. SiYuan supports offline access, and the maker describes multi-device synchronization as incremental and end-to-end encrypted. It is available on Windows, macOS, Linux, iOS, Android and the web, with a Chrome/Edge extension, API and Docker self-hosting. The maker says data stays under the user's control on their device. Free access is free; PRO Features is listed at $64 a month with lifetime-use wording, and Subscription at $148 a month with 8GB cloud storage.