RelayMail vs Slack's built-in email forwarding
Slack can already put email in a channel. On paid plans every channel and DM can get its own email address, and on every plan you can forward messages to Slackbot. If all you want is to see email in Slack, that is enough and it costs nothing extra.
What it does not do is send anything back. When a customer writes in, someone still has to open Gmail or Outlook, find the message and reply there. RelayMail adds that missing half: reply in the Slack thread and the customer gets an email.
How each one works
With Slack's forwarding you copy the channel's email address and set your mailbox to forward to it. Each email becomes a message in the channel. People can discuss it in a thread, but that thread never reaches the customer.
With RelayMail you also forward your address, to a RelayMail address instead. The email arrives in the channel you picked as the start of a thread. Anyone in the channel can reply in that thread; RelayMail sends the reply as an email in the same conversation, and when the customer answers, it lands back in the same thread.
What the customer sees
By default a RelayMail reply shows your name, is sent from RelayMail's relay address and has your own address as Reply-To, so the customer's answer comes back to you. If you verify your domain with a few DNS records, replies go out from your own address, for example support@yourcompany.com.
When Slack's email forwarding is the better pick
- –You only need to read email in Slack, and replies can keep happening in Gmail or Outlook.
- –Email is an occasional alert (receipts, monitoring, form notifications) rather than a conversation.
- –You do not want another subscription.
When RelayMail is the better pick
- ✓Customers or partners email a shared address like support@ or hello@ and the team already lives in Slack.
- ✓You want the whole back-and-forth in one Slack thread, with replies going out as normal email.
- ✓You do not want to give a tool your mailbox password or OAuth access; a forwarding rule is all it needs.
Questions
Can I reply to an email that Slack forwarded into a channel?
Not from Slack. Slack's forwarding is one-way. You can discuss it in a thread, but the sender only sees replies you send from your mail app.
Do I need a paid Slack plan for RelayMail?
No. RelayMail posts with its own Slack app, so it works on free and paid workspaces.
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See plans and start the trialUpdated 2026-10-07. Sources: