Mem Agent vs SiYuan

Mem Agent is an AI thought partner for capturing ideas, meetings and research, then retrieving them when needed. Mem Chat can answer workspace questions, create or update notes, organize them and draft content using workspace context. Deep Search accepts natural-language descriptions of what a user wants to find. Voice Mode records and transcribes meetings or spoken thoughts into structured notes. The Chrome extension captures and summarizes webpages and YouTube videos, organizes clips into collections and lets users edit notes from its popup; it is currently available only for Google Chrome. Mem connects to Google Calendar and Microsoft Outlook, but only displays meetings with two or more guests. It can connect to Claude to search Mem knowledge, save conversations as notes, update documents and organize a workspace. The free plan includes 25 messages and 25 new notes per month, tracking for 25 notes, 15 open tasks and projects, and three Voice Mode hours. Mem Plus costs $9 a month. Content is encrypted in transit and at rest, but is unencrypted for AI processing by trusted third-party vendors. Mem supports one-click exports of notes and collections as Markdown files.

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.