Client-Side AES-256-GCM Encryption
Message bodies, subjects, and stored attachments are encrypted with AES-256-GCM using keys derived via scrypt. Only minimal SMTP routing headers are processed for delivery.
Private Email That
Nobody Else Can Read.
Sovereign, zero-knowledge encrypted email infrastructure built for everyday personal and enterprise privacy. Messages and attachments are sealed with authenticated AES-256-GCM so only you hold the keys, with Direct-MX mail delivery, zero tracking pixels, hardware FIDO2 passkeys, and no phone number required.
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Security Built for Real-World Peace of Mind
Clear boundaries on what our servers can and cannot see, backed by our documented Security Architecture.
Sandbox Attachment Screening
Inbound external attachments are screened across 70+ threat engines via VirusTotal and Falcon Sandbox behavioral reputation intelligence at the MX boundary before being sealed into encrypted storage.
Bot-Free Signup & Inbox Deliverability
Instead of demanding your phone number, we review new handle requests (typically within hours) to keep spam botnets off our relays so your emails reliably reach recipient inboxes.
Zero Tracking & Zero Ads
Hidden 1x1 tracking pixels and remote marketing beacons are stripped automatically before rendering. Zero ad networks, zero behavioral profiling, and zero data brokerage.
How Natrium Works in 4 Steps
From anonymous handle reservation to client-side vault encryption in minutes.
PHASE 01
Reserve Your Handle
Choose your @natrium.sh address with zero phone number or personal ID required. Anti-abuse review typically completes within a few hours.
PHASE 02
One-Click Status Check
Your application is bound to a cryptographic browser token on this device—check approval status anytime with one click, no ticket codes needed.
PHASE 03
Client Key Derivation
Set your passphrase and optional FIDO2 hardware passkey. Encryption keys are derived via scrypt and never stored in plaintext.
PHASE 04
Encrypted Workspace
Send and receive mail worldwide over TLS 1.3 and 2048-bit DKIM in a fast, distraction-free dark workspace.
Natrium vs. Legacy Encrypted Providers
See how Natrium compares on attachment screening, anonymous signup, and cryptographic standards—or view our detailed architecture comparison.
| FEATURE / ARCHITECTURAL CAPABILITY | PROTON MAIL & TUTA | NATRIUM SECURE MAIL |
|---|---|---|
Inbound Attachment Screening Malware & macro inspection before vault storage | Basic static virus check with limited signature feeds | Pre-vault screening across 70+ threat engines and Falcon Sandbox intelligence |
Spam Prevention & Deliverability Protecting outbound SMTP IP reputation | Open signups attract botnets that degrade shared relay reputation | Human-reviewed handle requests block botnets and protect MX reputation |
Account Registration Requirements Personal identifiers required at signup | Often prompts for SMS phone verification or secondary recovery email | Zero phone numbers, SMS verification, or personal identifiers required |
Programmatic & AI Agent Access Standardized APIs for developer and agent workflows | Requires local desktop bridge apps or closed proprietary web interfaces | Documented OpenAPI 3.1, Model Context Protocol (MCP), and A2A endpoints |
Data Stored on Server What exists on disk under legal process or breach | Subject headers and contact metadata often remain accessible on disk | AES-256-GCM encrypted bodies, subjects, and .enc blobs; minimal routing headers |
Key Derivation & Authentication How keys and sessions are protected | Legacy OpenPGP keyring management with higher browser memory overhead | scrypt (N=32768, r=8, p=1) key derivation, AES-256-GCM, and FIDO2 passkeys |
Interface & Privacy Defaults Tracker blocking and workspace layout | Promotional upgrade banners and manual tracker-blocking configuration | Automatic 1x1 tracking pixel stripping in a distraction-free workspace |
Install Natrium Anywhere. Stay Truly Private.
Native binaries, desktop clients, and mobile wrappers built for speed, biometric security, and zero telemetry across every device.
Simple, Predictable Pricing for Private Email
No advertising, no data harvesting, no hidden telemetry. Start free forever or upgrade for custom domains and expanded storage.
Free
Essential zero-knowledge encrypted email for everyday personal privacy.
$0/ month forever
- 10 GB Encrypted Email Storage
- 3 @natrium.sh Addresses
- 25 MB Encrypted Attachments
- 2 Account Links & Identity Switching
RECOMMENDED
Pro
Expanded storage, larger attachments, and autonomous AI replies for power users.
$3.99/ month, billed annually
- 25 GB Encrypted Email Storage
- 5 @natrium.sh Addresses
- 100 MB Encrypted Attachments
- Autonomous AI Auto-Reply Engine
- Priority Support
- Up to 4 Linked Accounts
Enterprise
Team user provisioning, custom relays, and SIEM observability for organizations.
$11.99/ month per user, billed annually
- 50 GB Dedicated Storage
- Up to 3 Custom Domain Links
- Team User Provisioning & Admin Console
- Custom Outbound Relays & Dedicated MTA
- SIEM Observability & Real-Time Audit Logs
- 24/7 Dedicated Priority Incident Support
- Unlimited Linked Accounts
Frequently Asked Questions
Clear answers on how our encryption, pre-vault threat screening, and account vetting work.
No. Natrium uses AES-256-GCM encryption with keys derived via scrypt (N=32768, r=8, p=1) and protected by hardware passkeys. Message bodies, subjects, and .enc attachment blobs are stored strictly as authenticated ciphertext; only minimal RFC 5322 SMTP routing headers are processed for delivery, so we cannot produce message plaintext under subpoenas.
Open email signups without phone verification attract automated spam botnets that quickly ruin sender IP reputation. Instead of demanding your phone number or government ID, our anti-abuse team reviews handle requests (typically within a few hours) so every member enjoys reliable inbox deliverability.
Your access request status is tracked automatically on this device. Simply click "Check Status" on the navigation bar or hero section — your device signature and secure session token automatically query the vetting registry without needing to manually copy, remember, or paste a ticket serial number.
Because Natrium is truly zero-knowledge, your plaintext account password is never stored on our servers. You can recover account access using any of your configured recovery methods: your two-question Security Recovery challenge, enrolled Hardware Passkeys / FIDO2 WebAuthn authenticators, single-use 8-character 2FA backup codes, optional recovery email verification codes, or recognized trusted device reset authorization.
Yes, seamlessly. Natrium is fully interoperable with all standard RFC 5322 email clients and servers over opportunistic TLS 1.3 / 1.2 with 2048-bit DKIM, SPF, and DMARC alignment. When receiving mail from external services, Natrium automatically neutralizes tracking pixels and screens attachments before display.
Inbound external emails arrive at our MX boundary over TLS, where attachments are screened via SHA-256 threat intelligence queries against 70+ antivirus engines and Falcon Sandbox behavioral reputation feeds before being sealed with AES-256-GCM into your encrypted vault. For internal encrypted uploads, SHA-256 hash reputation checks verify safety without exposing file contents.
Account Links allow you to connect multiple Natrium mailboxes together and switch between identities with a single click without logging out. Free accounts can link up to 2 identities, Pro accounts can link up to 4 identities, and Enterprise accounts enjoy unlimited identity switching.
Yes! We believe strong physical authentication should never be locked behind a paywall. All Natrium accounts — including the Free tier — support biometric passkeys, Touch ID, Windows Hello, and hardware security keys (YubiKey / FIDO2 / WebAuthn) for phishing-resistant logins.
Exactly zero. Natrium operates with zero advertising networks, zero marketing pixels, and zero behavioral telemetry. Our business model is funded entirely by optional paid Pro and Enterprise subscriptions, keeping our incentives 100% aligned with your privacy.
Ready for Truly Private Email?
Reserve your @natrium.sh address today—no phone number or personal ID required. Most access requests are reviewed within a few hours.