Mem and SiYuan represent opposite ends of the PKM spectrum: Mem is a cloud-only, AI-first tool where you capture freely and let algorithms organize your notes, while SiYuan is a local-first, self-hostable, open-source block editor you control completely. The choice comes down to one question: do you trust a SaaS company with your knowledge and want AI to do the organizing, or do you want your notes on your own machine with full control over structure and storage?
Quick comparison
| Feature | Mem | SiYuan |
|---|---|---|
| Starting price | Free plan | Free plan |
| Free plan | Yes | Yes |
| Open source | No | Yes |
| Self-hostable | No | Yes |
| G2 rating | Not listed | Not listed |
| Best for | individuals who want frictionless AI-organized cloud note-taking | privacy-conscious users who want a local-first, self-hostable knowledge base |
| Starting price | Free plan available; paid tiers depend on usage and plan limits. | Free plan available; paid tiers depend on usage and plan limits. |
| Free plan | Yes | Yes |
| Open source | No | Yes |
| Self-hostable | No | Yes |
| Deployment model | saas | self-hosted |
| Best for | teams starting with productivity software on a free plan | self-hosted productivity software teams |
| Primary risk | Free-tier limits can hide the real cost until workflows reach production. | Requires internal ownership for hosting, upgrades, and security. |
Note-taking and linking model
SiYuan's block-based editor gives you fine-grained control over content structure that Mem simply doesn't offer. Every paragraph, heading, list item, and embed is a discrete block you can reference, embed, or link anywhere in your vault. Mem's linking is looser — you link between notes, not blocks. For users building a serious knowledge base with inline references and transclusion, SiYuan's model is more powerful. Mem wins on ease of capture, but if you're comparing linking depth and structural expressiveness, SiYuan is the more capable system. The trade-off is setup time: SiYuan requires you to think about structure upfront, while Mem handles it in the background.
Offline and local-first access
SiYuan is definitively local-first: your data lives on your device by default, sync is optional and self-controlled, and the app works fully offline without any degradation. You can self-host the sync server if you want sync without trusting a third party. Mem is the opposite — cloud-dependent by design, with offline access limited to cached reads. SiYuan's local-first architecture is particularly appealing for users in regions with unreliable connectivity, anyone who travels frequently, or professionals with data residency requirements. If your notes contain sensitive information and you're uncomfortable with vendor lock-in to a SaaS provider, SiYuan's model is the right choice.
Knowledge graph and backlinking
SiYuan's block-reference system creates a more granular and reliable graph than Mem's AI-inferred connections. Every block has a unique ID, backlinks are tracked precisely, and the graph view shows real relationships you've established rather than AI-suggested ones. Mem has a graph, but it's powered by AI pattern matching which sometimes surfaces unexpected or irrelevant connections. For users who want to see exactly how their ideas connect — and trust that those connections are ones they made explicitly — SiYuan's graph is more dependable. SiYuan also handles transclusion natively, letting you embed blocks from one note into another while keeping the content in sync.
Database and structured content
SiYuan has a proper database block feature that lets you create table-like views of your notes with custom attributes, filters, and sorting — similar to a lightweight Notion database. This is genuinely useful for tracking projects, reading lists, or any structured data. Mem has no database functionality; it's intentionally unstructured and relies on AI to surface relevant content instead of letting you build queryable records. For anyone who needs to manage structured data alongside free-form notes in a single tool, SiYuan's database blocks are a meaningful advantage. Mem's lack of structure is a feature for some users but a limitation for those coming from Notion or Obsidian with templated workflows.
AI and smart search
Mem was built around AI from the start and that shows. Mem X provides semantic search across your entire knowledge base, AI-powered note organization, automatic tagging, and smart suggestions for related content. It's the most integrated AI experience of any note-taking tool outside Notion AI. SiYuan has added AI features via plugins and its built-in AI assistant, but they feel secondary to its core strengths. If you want AI to actively maintain and surface your knowledge base without manual curation, Mem has a clear edge. SiYuan users who want AI assistance typically rely on integrations rather than native functionality, which adds friction.
Pricing for individuals and teams
SiYuan is open-source and free to use locally with no feature limits. The optional paid plan covers cloud sync hosted by the SiYuan team — if you self-host your sync, you pay nothing. This makes SiYuan essentially free for technically capable users. Mem's free tier is limited and the AI features that justify using Mem over a simpler note app sit behind a paid subscription. For budget-conscious individuals or anyone comfortable running their own infrastructure, SiYuan is the obvious winner on cost. The only exception is users who need AI auto-organization badly enough to pay for it — in that case Mem's total cost may be worth it.
Pricing deep-dive
Mem
- Free plan: available for evaluation or limited production use.
- Entry paid tier: starts from free with feature or usage upgrades on paid tiers.
- Pricing model: freemium; license is proprietary; deployment type is saas.
SiYuan
- Free plan: available for evaluation or limited production use.
- Entry paid tier: starts from free with feature or usage upgrades on paid tiers.
- Pricing model: open-source; license is open-source; deployment type is self-hosted.
- Open-source: subscription cost may be replaced by hosting, upgrades, and internal maintenance.
Pricing verdict: SiYuan wins on pricing for most users: it's free and open-source with no feature restrictions. You only pay if you want the team's managed sync service. Mem's free tier is limited and the AI features that define the product require a paid subscription. For self-hosters or users comfortable with local-first tools, SiYuan's total cost is zero. For Mem, budget for a recurring subscription if you want the AI capabilities that make it worth choosing over simpler alternatives.
How to migrate from Mem to SiYuan
What real users say
Mem: Mem users love the zero-friction capture and the experience of trusting AI to organize everything. The most common frustration is cost — Mem X is expensive for a note-taking app, and users question the value when the AI suggestions don't always feel relevant. Some users also express concern about vendor lock-in given how much the product depends on Mem's cloud infrastructure.
SiYuan: SiYuan users praise the depth of the block-reference system, local-first data ownership, and the fact that the core product is free. Common complaints center on the steep learning curve, the primarily Chinese-origin documentation which can feel inconsistent in English, and occasional sync reliability issues with the cloud service.
Sources: Pattern synthesized from catalog data, vendor positioning, and public review themes; verify on G2 or Capterra before quoting directly.
Final verdict
Choose Mem if...
- Choose Mem if you want AI to handle all organization automatically and you're willing to pay for that convenience.
- Choose Mem if you primarily capture ideas quickly across mobile and desktop and rely on search rather than structure to find things.
- Choose Mem if you've tried structured note tools and abandoned them because maintenance overhead killed your motivation.
Choose SiYuan if...
- Choose SiYuan if data ownership and privacy matter enough to rule out cloud-only tools.
- Choose SiYuan if you want block-level linking, transclusion, and database features that Mem doesn't offer.
- Choose SiYuan if you want a powerful, fully-featured knowledge base tool at zero cost and are comfortable with self-hosted software.
Consider neither if: Consider neither if you want something in between — structured but cloud-friendly — and consider Obsidian (local Markdown with optional sync), Notion (cloud with databases), or Logseq (local-first block-based, fully open-source and free).