How to send an email from Slack and get the answer back in Slack

Most email a team sends from Slack is a reply, but sometimes the conversation has to start on your side: following up with a customer, asking a supplier for a date, writing to someone who hasn't emailed you yet. With RelayMail you write that email in Slack, it goes out from your team address, and the answer lands in a Slack thread where the whole channel can see it.

Write it with /email

In the channel connected to your RelayMail inbox, type /email, or /email followed by an address to fill in the To field. A form opens with To, Cc, Subject and Message. To and Cc take one or more addresses separated by commas, up to 10 in all.

Press Send. The email goes out from your inbox the same way a thread reply does: with your name and your team address as Reply-To, or from your own address (for example support@yourcompany.com) once your domain is verified. Bold, italics, links and lists you type in the message show in the email, and your email signature is added if you turned it on.

The email then appears in the channel as a new thread. When the person answers, their email lands in that thread, and a reply there goes back to them, and to anyone else on the email, as a normal email.

Who can use it

The same "Who can send email replies" setting decides who can use /email: anyone in the channel, only the inbox owner and admins, or people you pick. Someone who isn't allowed gets a private note and nothing is sent. Each email sent with /email counts as one thread on your plan.

Slack connections made before November 13, 2026 need one reconnect to turn /email on, because Slack asks for permission to add a command. The setup page shows a Reconnect Slack link when that applies; your channel and settings stay the same.

Other ways to send an email from Slack

Slack's Workflow Builder has a Send an email step for Gmail and for Outlook on paid Slack plans. The email goes out from the account of the person running the workflow, and any answer arrives in that person's own mailbox, not in Slack.

SharedInbox has a /compose command that sends a new email from Slack. It connects to your mail account with a Google app password or a Microsoft sign-in, where RelayMail works from a forwarding rule and never logs in to the mailbox.

When Workflow Builder and SharedInbox is the better pick

×Use Workflow Builder's Send an email step if the email should come from your own Gmail or Outlook account and the answer can arrive in your mailbox.
×Use SharedInbox if you would rather connect your mailbox directly, or want to assign emails, set a status and a due date.

When RelayMail is the better pick

✓Use RelayMail if the email should come from a shared team address and the answer should come back to Slack, where the whole channel can pick it up.

Questions

Does the person I email need Slack?

No. They get a normal email and answer it from their own mail app. Their answer shows up in your Slack thread.

Where does the answer go?

Into the Slack thread the email started, in the channel connected to your inbox. Mail apps keep a reference to the original email in every answer, which is how RelayMail finds the thread.

Can I attach a file?

Not in the /email form. Send the email, then reply in its thread with the file attached: the reply goes out as an email with the file, up to 10 files and 20 MB in total.

Can I copy other people?

Yes. Put them in Cc, or add several addresses to To. Up to 10 addresses per email, and later replies in the thread copy them too.

Try RelayMail on your real inbox for 14 days

$0 today, then from $15/month per inbox. Cancel in Billing before day 14 and you pay nothing.

See plans and start the trial

Updated 2026-11-13. How we check these pages. Sources: