Where Your Memo Travels,
and Where It Never Stays
"It writes to my local vault — so why does a server appear at all?" This is the question we hear most from Obsidian users, and this page answers it as a route map. What we do well (local-only vault appends, on-device AI, no server retention) and what we deliberately don't do (end-to-end encryption) are written at the same resolution.
The data path of a single memo
- Created on your device — protected with AES-GCM-256A memo first enters the on-device Outbox (the unsent queue). Simple Memo - for Obsidian encrypts the on-device Outbox queue and send history with AES-GCM-256 via Apple's CryptoKit; the 256-bit symmetric key lives in Apple Keychain, never leaves the device, and is excluded from backups. Offline, the memo waits here and auto-resends when the connection returns.
- Append to your Obsidian vault — entirely localWith the Obsidian integration enabled, the append is a direct file write into the vault folder on your device (with a URI fallback when direct access isn't possible). No plugin, no external server — the network never appears in this path.
- AI tagging — completed on-deviceThe automatic title (up to 20 characters), 1–3 tags, and type (todo / idea / log) are generated by on-device AI via Apple Foundation Models, entirely on your iPhone. Memos are not sent to an external server for tagging. Devices without Apple Intelligence fall back automatically to on-device lightweight formatting.
- Email send — passes through over TLS, never storedOnly at send time does the body pass through our relay API (Cloudflare Workers) and the delivery provider (Resend), over TLS. Memo bodies are not persistently stored on our servers, and they are not written to logs. The client uses
URLSessionConfiguration.ephemeral— no cookies, no caches. - Into your own inbox — delivered over standard SMTP (= not E2EE)Final delivery is standard SMTP. That is exactly why you can read your memos in your regular mail client — and also why Simple Memo - for Obsidian is not end-to-end encrypted. See "Stated plainly" below for the reasoning behind this trade-off.
What stays on a server — and what never does
| Data | Where | Retained? |
|---|---|---|
| Memo body | Our servers (relay / delivery) | No — transit only during send, not logged |
| Memo body | Your email inbox | Yes (that is the point) |
| Memo body | Your Obsidian vault (if enabled) | Yes — local, on your device |
| Outbox & send history | On-device only | Encrypted with AES-GCM-256 |
| Email address | Cloudflare D1 | Only a SHA-256 hash, and only if you opt into reminder emails (the raw address lives only in Resend's Contact API) |
| Tagging input (memo body) | External servers | Never sent — processing is on-device |
Zero third-party SDKs on the data path
Encryption (CryptoKit), key storage (Keychain Services), and networking (URLSession / Network.framework) are all first-party Apple frameworks — there are zero third-party SDKs in the encryption / storage / network-transport pipeline. SDKs used for optional features are scoped and listed: Google sign-in for email auto-fill in onboarding (GoogleSignIn-iOS + Firebase Authentication), backend API abuse protection (Firebase App Check with Apple App Attest), and in-house funnel analytics with no PII. None of these touch the memo-body data path.
Stated plainly — this is not E2EE
Simple Memo - for Obsidian is not end-to-end encrypted — emails are delivered over standard SMTP. "Readable in your regular mail client" and "only you hold the decryption key at every hop" cannot both be true; we chose the former, by design.
The on-device Outbox queue and send history are encrypted with AES-GCM-256, but that is on-device protection, not a substitute for E2EE (what E2EE is, and why this app doesn't qualify).
If E2EE is a hard requirement for you, an E2EE-designed notes app such as Standard Notes is the better fit. With that stated, our commitments are: memo bodies never stored on our servers, tagging completed on-device, and vault appends performed locally.
Frequently asked questions
Is any external server involved in the Obsidian vault append?
No. The append is a direct file write into the vault folder on your device (URI fallback when direct access isn't available), with no plugin and no network involved. Local draft saves that don't involve sending an email also stay entirely on-device.
Does AI tagging send my memo to Apple or anyone else's servers?
No. Tagging runs on-device via Apple Foundation Models with no network calls, and memos are not sent to an external server for tagging. On devices without Apple Intelligence, it falls back to on-device lightweight formatting — still with nothing sent externally. Details on the AI auto-tagging page.
Why not make it E2EE?
Because the destination is your everyday email inbox. If your mail server can show you the memo, it can decrypt it — so E2EE is structurally impossible here. Choosing E2EE would require a dedicated client and give up the "readable on any device, in any mail app" property this app exists for. For E2EE-first needs we genuinely recommend Standard Notes and similar apps.
How does this page relate to the Privacy Policy?
The legally binding text is the Privacy Policy (especially §12, "Technical notes on encryption"). This page rearranges the same facts as a route map, organized around what Obsidian users ask most — whether things stay local. If they ever disagree, the Privacy Policy wins.
