Stax Inbox
Coming Soon

One Login.
Every Email Account.
Every Device.

Set up all your email accounts once. Stax Inbox syncs your encrypted configuration to every device automatically — no more entering the same credentials 50 times.

The Problem

  • 10 email accounts × 5 devices = 50 manual setups
  • IMAP credentials re-entered on every new phone
  • No existing client syncs account settings across devices
  • Switching phones means starting from scratch

Stax Inbox

  • Set up all accounts once on any device
  • Every other device picks them up automatically
  • Encrypted config sync — your passwords never leave your device in plain text
  • New phone? Sign in once. Done.

Everything you need.
Nothing you don't.

Built for people who manage multiple email accounts across multiple providers and are tired of the setup tax.

🔐

Zero-Knowledge Encryption

Your email passwords are encrypted on your device before they ever reach our servers. We use AES-256-GCM with a key derived from your master password. We can never see your credentials.

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Cross-Device Sync

Add an account on your phone. Open the app on your Mac. It's already there. Encrypted config syncs automatically across iOS, Android, macOS, Windows, and web.

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Any Email Provider

Works with Gmail, Outlook, Fastmail, MXRoute, Migadu, Yahoo, or any IMAP/SMTP server. If it speaks email standards, Stax Inbox supports it.

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Direct IMAP/SMTP

Your emails travel directly between the app and your mail provider. Stax Inbox's servers never see your email content — only your encrypted account configuration.

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All Platforms

iOS, Android, macOS, Windows, and web — one codebase, one experience, everywhere. Your setup follows you regardless of what device you're on.

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One Master Password

A single master login unlocks all your accounts on every device. Change your master password and everything re-encrypts automatically. No recovery key needed.

We believe in open security.

Our encryption model is documented publicly. Security comes from the math, not from keeping the method secret.

How zero-knowledge works

Your master password never leaves your device as a key. Here is exactly what happens:

  • 1

    You create a master account. We store a bcrypt hash of your master password for login authentication. The plaintext never persists.

  • 2

    Your device derives an encryption key. Using Argon2/PBKDF2 (a slow, salted key derivation function), your device generates a 256-bit AES key from your master password. This key never leaves your device.

  • 3

    Email passwords are encrypted locally. Before any credential is sent to our servers, it is encrypted with AES-256-GCM using your device-local key. We receive only the encrypted blob.

  • 4

    Other devices decrypt locally. A new device logs in, downloads your encrypted blobs, and derives the same key from your master password. Decryption happens entirely on-device.

  • 5

    Same password → same key, everywhere. Argon2/PBKDF2 is deterministic: same password + same salt = same 256-bit key on any device. No key transmission required.

Cryptographic Primitives
Email password encryptionAES-256-GCM
Key derivationArgon2 / PBKDF2
Login auth (server)bcrypt
Key length256-bit
Key transmission to serverNever
Email traffic via our serverNever
What our server stores per email account
Field Encrypted?
Email addressPlain
Display name / labelPlain
IMAP host, port, securityPlain
SMTP host, port, securityPlain
IMAP usernamePlain
IMAP passwordAES-256-GCM
SMTP passwordAES-256-GCM
OAuth refresh tokenAES-256-GCM

Set up once. Sync everywhere.

Three steps to never configure email accounts again.

1

Create Your Master Account

One email and master password. This is your single login for all devices.

2

Add Your Email Accounts

Enter each email account's credentials once. They're encrypted on your device and synced to our servers.

3

Open on Any Device

Sign in with your master password on any new device. All your accounts appear — already configured.

Get early access.

Stax Inbox is currently in development. Leave your email and we'll notify you when it launches.