SMTP vs IMAP: what Distro users need to know

SMTP sends email. IMAP reads email that's already in a mailbox. Many email tools ask you for both so they can send campaigns and watch for replies. Distro doesn't: it connects to your Google account (Gmail or Google Workspace) through Google's own sign-in and APIs, so you don't give Distro any SMTP or IMAP credentials.

SMTP in plain words

SMTP (Simple Mail Transfer Protocol) is how email moves from one server to the next. When you press send, your mail app hands the message to an outgoing SMTP server, which passes it towards the recipient's mail server.

To use a provider's SMTP server, an app needs:

• the server name (the outgoing mail server),
• a port, commonly 465 (SSL) or 587 (TLS/STARTTLS), though providers differ,
• a username and password (or an app password) for the mailbox,
• the security type to use.

IMAP in plain words

IMAP (Internet Message Access Protocol) lets an app read and organise the mail stored in a mailbox: see new messages, open them, mark them read, move them to folders. It doesn't send anything. A tool that tracks replies over IMAP logs in to your mailbox with a username and password and checks for new mail.

You may also see POP3, an older way of downloading mail. Distro doesn't use it either.

Side by side

Why Distro doesn't need separate IMAP credentials

Distro connects to your Google account (Gmail or Google Workspace) with Google sign-in (OAuth). When you connect, Google asks you to allow two permissions: one to send email as you, and one to read your mailbox in read-only mode. With those, Distro uses Google's APIs directly:

• Sending goes through the Gmail API, from your own Google account.
• Replies are found through the Gmail API. Distro looks for messages that belong to its own email threads (replies, bounces, out-of-office notes), keeps those, and ignores the rest of your mail.
• Your sending addresses are read from your Gmail "Send mail as" list, also through the API.

So there is nothing for IMAP or SMTP to do, and nothing to type in:

• Distro never asks for your Google password. You sign in on Google's own page.
• There's no app password to create.
• You can remove access any time by disconnecting in Distro or from your Google account's security settings.

More detail: What Google permissions Distro needs and How Distro sends email.

So where does SMTP come up?

Only inside Gmail, and only in one situation: when you add a sending address that's hosted at another provider under Gmail's Send mail as setting. Gmail may then ask for that provider's SMTP details so it can send that address's mail through the provider's server. You enter them in Gmail, not in Distro, and they come from your provider. See Gmail is asking for SMTP settings and Where to find SMTP settings from your email provider.

Google Workspace aliases don't usually need any of this. They belong to the same Google user, so Gmail sends them directly. See How to add a Google Workspace alias.

Quick answers

A guide told me to turn on IMAP in Gmail settings. Do I need to for Distro? No. Distro doesn't use IMAP, so that setting doesn't affect it.

Can I connect a non-Google mailbox with SMTP and IMAP instead? Not today. If your company email is hosted elsewhere, see the options in Send cold email from your custom-domain email.

Does Distro read all my email? No. It reads only messages linked to emails Distro sent, such as replies and bounces, and doesn't keep unrelated mail.