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Create your account & first sign-in

How to sign in to Letro for the first time and get into your encrypted conversations.

Your PostNumber is the unique identity you use to sign in to Letro. If you create your own account, you choose its numeric part, provided it is available and not reserved. If you're an organization member, your organization provides your PostNumber and sign-in details.

Security note: Right after your first sign-in, Letro will prompt you to set up a secure backup and a recovery key. Don't skip this — it's what lets you get back into your encrypted messages if you lose a device. See Set up secure backup & key storage.

Before you start

  • Make sure you've installed Letro — see Download & install Letro.
  • Have your sign-in details ready. Depending on your organization, that's either a PostNumber (or username) and password, or Sign in with Google.

Choosing your server

If your company uses a Letro Dedicated Server — a private, encrypted environment on your organization's own infrastructure — you'll point Letro at that server the first time you sign in. Your company provides the server address (for example yourcompany.s.letro.com); enter it when Letro asks which server to connect to.

If you're not a Dedicated Server customer, Letro connects to its hosted server for you and you won't see this step. Learn more in What is a Letro Dedicated Server.

On Web & Desktop

  1. Open Letro in your browser or launch the desktop app. You'll see the welcome screen.
  2. Select Sign in.
  3. If you're a Dedicated Server customer, enter your organization's server address when prompted.
  4. To use single sign-on, select Sign in with Google and complete sign-in with your Google account.
  5. Otherwise, enter your PostNumber (or username) and password, then select Continue.
  6. If prompted, accept the terms to continue.
  7. If your account uses email verification, open the email Letro sends and confirm to finish signing in.
  8. Once you're in, follow the prompt to set up secure backup.

On iOS

  1. Open Letro. You'll see the welcome screen.
  2. Tap Sign in.
  3. If you're a Dedicated Server customer, enter your organization's server address when prompted.
  4. To use single sign-on, tap Sign in with Google and complete sign-in with your Google account.
  5. Otherwise, enter your PostNumber (or username) and password, then tap Continue.
  6. If prompted, accept the terms and confirm any email verification.
  7. Follow the prompt to set up secure backup.

On Android

  1. Open Letro. You'll see the welcome screen.
  2. Tap Sign in.
  3. If you're a Dedicated Server customer, enter your organization's server address when prompted.
  4. To use single sign-on, tap Sign in with Google and complete sign-in with your Google account.
  5. Otherwise, enter your PostNumber (or username) and password, then tap Continue.
  6. If prompted, accept the terms and confirm any email verification.
  7. Follow the prompt to set up secure backup.

Signing in on an additional device

If you already use Letro on another device, signing in on a new one is a verification, not a fresh account. Letro will ask you to confirm the new device from a device you already trust, or to enter your recovery key. This keeps your encrypted history available on the new device. See Verify your own devices.

Good to know

  • Personal accounts use a number you choose. During registration, choose the numeric part of your PostNumber. If it is unavailable or reserved, choose another one.
  • Organizations manage their members' accounts. If your organization provided your PostNumber, it can manage the account and revoke access when you leave.
  • Dedicated Server customers connect to their own server. If your company runs a Letro Dedicated Server, you enter its address once at sign-in; everyone else connects to Letro's hosted server automatically. See What is a Letro Dedicated Server.
  • Forgot your password? If you sign in with a PostNumber (or username) and password, you can reset it — see Recover a locked-out account. If you use Sign in with Google, reset it through your Google account.
  • Set up your recovery key early. It's the one thing that can restore your encrypted messages if you lose access to all your devices. See Your recovery key.

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