Terms of Service

Last updated 9 September 2026

Courier is a desktop email program, provided free of charge and as-is. You keep your own mail accounts with your own providers; Courier is software that talks to them from your computer. These terms are short because there is not much between us: no account, no subscription, and nothing of yours held on our side.

1. What you may do with it

You may install and use Courier on as many of your own machines as you like, for personal or business purposes, at no cost. That is a permission to use the program, not a transfer of any rights in it: Courier's source is published so that anyone can read what it does, but it carries no open source licence and all rights are reserved. You may not sell it, redistribute it, or publish a modified build of it — under the Courier name or any other.

2. It comes with no warranty

Courier is provided "as is", without warranty of any kind, express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, and non-infringement. We do not promise that it is free of defects, that it will work with every mail provider, or that it will be available or maintained indefinitely.

That is not boilerplate to skim past. Email software fails in ways that matter: a message can fail to send, a sync can be incomplete, and a provider can change its rules without notice. Courier is not a backup of your mail. Its local database is a copy of what is on your provider's servers, and it should be treated that way.

3. Your accounts, and your provider's rules

You are responsible for the mail accounts you connect and for complying with the terms of whoever provides them. Courier only does what you ask it to with those accounts. Note that a provider can suspend or restrict access on its own initiative — for instance by disabling IMAP, or by limiting which applications may sign in — and when that happens there is nothing Courier can do about it from your side.

Actions you take in Courier reach a real mail server. Deleting a message moves it to your provider's Trash rather than destroying it, but sending is not reversible, and neither is anything you then do in your provider's own web interface.

4. Updates

Courier checks for new versions and can install them. Every build is cryptographically signed, and the app refuses any update that is not signed with the expected key. Updates may change or remove features.

5. Acceptable use

Do not use Courier to send unsolicited bulk mail, to impersonate someone else, or for anything unlawful where you are. This is a normal condition of using any mail software, and your provider almost certainly says the same thing.

6. Limitation of liability

To the fullest extent permitted by applicable law, we are not liable for any indirect, incidental, special or consequential damages, or for lost mail, lost data, lost profits or business interruption, arising from your use of or inability to use Courier — even if we were told such damage was possible. Since the software is supplied at no charge, no fee has been paid against which a claim could be measured.

Nothing here limits liability that cannot be limited by law, and if you are a consumer, your statutory rights are unaffected by these terms.

7. Changes to these terms

These terms may change; the date at the top changes with them. Continuing to use Courier after a change means the new terms apply. If you do not accept them, uninstall the application — there is no account to close.

8. Contact

richard.kovari@hyperfocus.net.