RelayMail vs Unthread for answering email in Slack

Unthread and RelayMail both connect a support address to Slack with a forwarding rule, and both send a reply written in Slack back to the customer as an email. Neither one needs your mailbox password.

Unthread is a full support platform built on Slack, with email as one of its channels and plans priced per agent. RelayMail does only the email part: each email is a thread in the channel you pick, and plans are priced per inbox.

RelayMail

Unthread

Reply from Slack

Yes, a normal message in the thread

Yes, end the message with /unthread send (a workspace setting can require it)

How email gets in

A forwarding rule

Replies come from

RelayMail's relay address with your address as Reply-To, or your own domain once verified

@mail.unthread.io, or your own domain once verified

Pricing model

Per inbox, no seat fees

Per agent, minimum 5 seats

Entry price

$15/month per inbox (1,000 threads)

Pro from $85 per agent per month, minimum 5 seats

A support platform or an email relay

Unthread is built for support teams that run their whole queue in Slack, with email alongside requests that start in Slack itself. Its Pro plan starts at $85 per agent per month with a minimum of 5 seats, and Unthread notes that conversation limits apply.

RelayMail is for teams that only need customer email in a channel and an answer from the thread. Plans are $15, $39 or $149 a month per inbox by volume, with any number of teammates replying.

Sending a reply

In Unthread you write the reply in the thread and end it with /unthread send; a workspace setting decides whether that command is required. In RelayMail every message in the thread is emailed unless it starts with // or an @mention, which keeps it as a team note.

When Unthread is the better pick

×You want a support platform in Slack that handles requests from Slack channels as well as email.
×You have a support team of five or more and want per-agent tooling around the queue.

When RelayMail is the better pick

✓A small team answers email from one channel and five seats at $85 is more than you need.
✓You want plain Slack threads, with replies sent by writing in the thread.

Questions

Does Unthread work in a Slack Connect channel?

Unthread says the channel for an email inbox must be an internal channel, not a Slack Connect or shared channel.

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 2026-11-08. How we check these pages. Sources: