Which one should you pick?
Unabyss
Choose Unabyss if you want the work done for you and are comfortable with a vendor holding the context. Its auto-import from 20-odd sources, its official Claude connector, its per-seat team plan with central billing: these are real conveniences, paid for monthly.
Second Brain
Choose Second Brain if the context is the asset and it should sit in an account you control. You connect sources yourself, capture on purpose, and personal use fits inside Cloudflare’s free tier. The license is MIT, forever, and there is no third party in the path between your tools and your memory.
How they compare
| Criterion | Second Brain | Unabyss |
|---|---|---|
| Where the memory lives | In your Cloudflare account: D1, Vectorize and the Worker all inside it, unreadable to the maintainers. | Unabyss’s cloud, at app.unabyss.com; EU users get EU-hosted data. unabyss.com, checked 6 Sep 2026. |
| Who can read it | You, from any MCP client or the dashboard, over OAuth. | Unabyss operates the storage; it states AES-256 at rest, TLS 1.3 in transit, scoped OAuth per source with instant revocation, and no selling or AI training on your data. unabyss.com, checked 6 Sep 2026. |
| Tools and sources | Any MCP client (Claude, Claude Code, ChatGPT, Cursor and the rest), plus Obsidian, Notion, read-only calendar and email, iOS Shortcuts, the CLI and a bookmarklet. | MCP-native and an official Claude connector for Claude, ChatGPT, Cursor, Codex, Gemini, Perplexity, VS Code, Grok and more; auto-import from Slack, Gmail, Notion, Calendar, GitHub, LinkedIn, HubSpot, Pipedrive, Drive, Obsidian, OneNote and 20+ further sources. unabyss.com, checked 6 Sep 2026. |
| Coherence over months | Every capture is compared by meaning: contradictions settle on the newer belief with the older kept for audit, near-duplicates merge or replace, and 95 per cent matches are blocked. | It auto-extracts and updates context files; dedupe and contradiction handling are not published, so we cannot compare them. unabyss.com, checked 6 Sep 2026. |
| Teams | Personal and shared layers on one Worker, private by default, at no extra charge. | A Team plan at $39 per seat a month billed annually, $49 month to month, minimum three seats, with a shared workspace, email invites and central billing. unabyss.com, checked 6 Sep 2026. |
| Cost | Free at personal scale inside Cloudflare’s free tier; MIT-licensed forever, no paid tier. | Pro $13 a month billed annually ($15 monthly) for up to three MCP agents and 20 connected accounts; Max $79 ($89 monthly) for unlimited; every tier has a 7-day free trial and no free tier is advertised. unabyss.com, checked 6 Sep 2026. |
| Setup | The desktop app provisions the database, index and Worker in about two minutes, no terminal. | The vendor states under 90 seconds: connect sources, then MCP or direct export. unabyss.com, checked 6 Sep 2026. |
| Export | JSON backup and Markdown export from the dashboard, with restore. | You can export your context files and paste them into any AI tool. unabyss.com, checked 6 Sep 2026. |
| License | MIT. | No public repository or license is published on unabyss.com, so the code is not publicly auditable. unabyss.com, checked 6 Sep 2026. |
Where Unabyss wins
Unabyss wins on hands-off breadth. It reads LinkedIn, Slack, Gmail, Notion, GitHub and another twenty-odd sources without you saving anything, and there is nothing to deploy or keep updated. The official Claude connector listing makes the first connection one click. Its scoped OAuth with instant revocation and EU residency options are a serious posture. The per-seat team plan with a shared workspace and central invoicing has no equivalent here: Second Brain’s team layer is free and self-run, with each member connecting under their own token.
Common questions
Does Second Brain auto-import the way Unabyss does?
Not automatically. Captures are deliberate: you save from a client, the CLI, iOS Shortcuts, a bookmarklet or the dashboard. Calendar and email do sync, read-only, from published ICS and inbox mail. If you want LinkedIn and Slack ingested without ever pressing save, Unabyss does that and Second Brain does not.
Is Second Brain more private?
The architectures differ rather than one being simply safer. With Second Brain there is no third party in the path: the memory sits in your Cloudflare account and the maintainers cannot read it. Unabyss states AES-256 at rest, TLS 1.3 in transit, scoped OAuth and no training on your data, but the vendor operates the storage.
Do both work with Claude, ChatGPT and Cursor?
Yes. Both are MCP-native. Second Brain adds OAuth on its own endpoint, so you connect clients without pasting tokens into config files, and one address serves every tool on every device.
What does Second Brain cost?
Nothing at personal scale: it fits inside Cloudflare’s free tier, and the license is MIT, forever, stated as a promise rather than a launch price. Your Cloudflare account is the only vendor involved. Unabyss’s tiers start at $13 a month billed annually.
What happens if the service stops?
Second Brain keeps running regardless of us: it is MIT-licensed and deployed in your account, so the project outliving its maintainer does not take your memory with it, and JSON and Markdown exports exist anyway. Unabyss lets you export your context files; beyond that, continuity is the vendor’s to assure. For a place where thinking is meant to pile up, outlasting the maintainer is rather the point.
Sources
- unabyss.com homepage, pricing and FAQ (checked 6 September 2026)
- github.com/rahilp/second-brain-cloudflare and its wiki (checked 6 September 2026)