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Most buyers should pick Obsidian.
Pick Obsidian if you want a free, offline-capable Markdown vault you control, and can live without built-in AI retrieval. Its notes stay as local plain-text files; Sync costs $4 per user/month billed annually or $5 monthly. Pick Mem if you want AI search, note chat, voice capture, and calendar briefings, but check the caps: Mem Plus is $9/month for 50 messages and 50 new notes monthly; annual pricing is not published.
01Side by side
| Obsidian | Mem | |
|---|---|---|
| Starting price | Free; Sync is $4/user/month billed annually | Free; Mem Plus costs $9/month |
| Free plan | Free without limits; no sign-up required | 25 messages and 25 new notes monthly |
| Best for | Private, customizable Markdown knowledge management | AI-powered retrieval, capture, and task tracking |
| Core strength | Local files, note links, graph, and Canvas | Chat with notes and search by meaning |
| Learning curve | Not published | Not published |
| Data and capture | Local Markdown files; plugins and open API | Chrome clipper, email capture, and calendar sync |
| Team/seat costs | Commercial is $50/user/year; Sync is per user | Plans are $9-$199/month; seat basis not published |
| Support | Priority support on Sync and Publish | Support details not published |
Obsidian Choose Obsidian if
- Choose Obsidian if you want notes stored as local Markdown files.
- Choose Obsidian if a free personal vault covers your needs.
- Choose Obsidian if you want optional end-to-end encrypted sync.
Mem Choose Mem if
- Choose Mem if you want to ask questions of stored notes.
- Choose Mem if voice capture and transcription fit your workflow.
- Choose Mem if you accept monthly usage limits and tier upgrades.
02Pricing compared
Obsidian’s core note-taking app is free, with no limits and no sign-up required. Sync is optional: the pricing page lists it at $4 per user/month billed annually or $5 monthly. Publishing notes costs $8 per site/month annually or $10 monthly. Mem also has a free plan, but its limits include 25 messages to Mem, 25 new notes per month, 15 open tasks and projects, and 3 Voice Mode hours. Mem Plus costs $9/month and raises those limits to 50 messages, 50 new notes, 25 open tasks and projects, and 10 Voice Mode hours. Mem Pro starts at $29/month; higher tiers reach $199/month. Annual prices are not published. Mem lists a $50/month extra-usage block for Pro 20×, and no standard per-unit overage fees.
03Features and depth
Obsidian is built around local Markdown files: notes stay on your device as plain text and remain accessible offline. Links connect notes, while Graph view visualizes their relationships. Canvas provides an open space for arranging research and ideas; plugins, themes, and an open API let users customize the workspace. Sync adds encrypted syncing across devices, while Publish is a separate option for putting notes on the web. Mem takes an AI-first approach. Mem Agent can answer questions about stored notes, synthesize information, draft content, and track project tasks. Smart Search finds notes by meaning and suggests related notes. Mem also lists voice recording and transcription, a Chrome clipper, email forwarding, calendar briefings, and automatic topic-based collections. The choice is less about which has more features than what you want them to do: Obsidian gives you a flexible file-based knowledge system; Mem adds built-in AI retrieval and capture tools, subject to plan limits.
04Ease of use and learning curve
Obsidian requires no sign-up for its free app, and its Markdown files are plain text. That gives users direct access to their notes, but its links, Graph view, Canvas, plugins, and themes leave room to shape your own system. The published product details do not specify how much setup each feature takes. Mem’s capture options—including voice, email forwarding, and a browser clipper—and automatic collections are designed to gather and connect information. Its AI assistant can help retrieve notes without relying on exact keywords. But Mem’s message, note, and voice limits vary by plan, so frequent use may mean paying more. Choose based on whether you prefer to configure a file-based workspace or use an AI-centered service with published usage caps.
Questions people ask
Is Obsidian free to use?
Yes. Obsidian’s pricing page lists a free plan for personal note-taking with no limits and no sign-up required. Syncing and publishing are separate paid options: Sync starts at $4 per user/month with annual billing, and Publish starts at $8 per site/month annually.
Does Obsidian sync notes across devices?
Yes, through the optional Sync plan. The pricing page lists Sync at $4 per user/month when billed annually or $5 monthly. It includes end-to-end encryption, version history, collaboration on shared vaults, and priority support.
Does Mem have a free plan?
Yes. Mem Free includes 25 messages to Mem, 25 new notes per month, tracking for 25 notes, 15 open tasks and projects, and 3 Voice Mode hours. Mem’s pricing information does not publish annual-billing prices.
Which app is better for AI note search?
Mem is the clearer fit if you want AI search and chat: its Smart Search finds notes by meaning, and Mem Agent can answer questions about stored notes. Obsidian’s published feature list focuses on Markdown files, links, Graph view, Canvas, and customization rather than AI retrieval.