Short answer: very few follow-up tools cover both Slack and email. autoremind.ai does: it sends follow-ups to clients from your own Gmail and chases teammates in Slack, writing each message for you and stopping when they reply. Slack's built-in /remind handles simple repeating reminders inside Slack for free. Boomerang, FollowUp.cc and Mixmax are email tools.
Competitor details below were checked on each company's own site on 2026-10-01.
Table of Contents
Why one tool for both channels
If you run a small team or freelance with a few long-term clients, your open loops are split. The client who owes you an invoice is in email. The teammate who owes you a review is in Slack. Using two tools means two places to check what is still waiting, and two different habits for chasing.
A tool that covers both lets you keep one list of "who still owes me a reply", whichever channel the answer comes back on.
The options
autoremind.ai
Best for: small teams and freelancers whose follow-ups are split between clients in email and teammates in Slack.
Disclosure: this is our product.
You describe the follow-up in one sentence ("chase Sam for the Q3 numbers by Thursday"). autoremind.ai writes the messages and sends them on a schedule, getting firmer with each unanswered attempt: professional, then firm, then urgent. For outside contacts it sends from your own Gmail in the original thread. For people on your team it can send in Slack. When they reply to an email, it stops; Slack replies are not detected, so you close a Slack reminder yourself.
Try it on yours
Edit the sentence and press Continue. Free for 3 reminders, no card.
Where it falls short:
- Gmail only for email. No Outlook yet, no Microsoft Teams
- At most 4 messages per reminder
- Slack is for internal chases, not for messaging clients in their own workspace
Pricing: free for 3 live reminders, no card. Starter is $4/month for 10.
Slack /remind (built in)
Best for: simple, repeating reminders inside Slack, at no cost.
Slack's /remind command can post a reminder to yourself, a person or a channel, for example /remind #marketing-team to submit expenses every Thursday. According to Slack's help centre (2026-10-01), reminders can repeat by day but not by hour.
Where it falls short:
- The same text every time; nothing gets firmer
- It does not know whether the person answered, so it does not stop on reply
- No email at all
We cover the syntax in Slack recurring reminders with /remind.
Boomerang
Best for: Gmail users who need a nudge and write their own follow-ups.
Boomerang's Send Later and Boomerang Reminders bring a message back to your inbox if nobody replies by a date you choose. Respondable, its AI writing assistant, is on paid plans.
Where it falls short:
- It reminds you; it does not send the follow-up for you
- Email only, no Slack
Pricing (as of 2026-10-01): free Basic plan with 10 message credits a month; Personal $4.98/month, Pro $14.98/month, Premium $49.98/month, billed annually.
FollowUp.cc
Best for: Gmail users who want follow-ups they wrote themselves to go out automatically.
As of 2026-10-01 FollowUp.cc is an active Gmail add-on with reminders, open and click tracking, send later, and follow-ups that "send automatically if your recipient doesn't reply". You write those in advance or use its templates.
Where it falls short:
- Email only, no Slack
- You write the follow-ups
- Priced above most single-user tools
Pricing (as of 2026-10-01): Starter $18/month billed annually ($23 monthly), Professional $29 ($36), Salesforce Edition $40 ($50). 14-day free trial, no card.
Mixmax
Best for: sales reps running sequences from Gmail.
Mixmax adds tracking, reminders, scheduling and sequences to Gmail. Sequences stop for a recipient when they reply, by default. AI features include Smart compose and an AI sequence builder on some plans.
Where it falls short:
- Email only, no Slack follow-ups
- Built and priced for sales teams
Pricing (as of 2026-10-01): 14-day trial then a free plan (sequences capped at 50 recipients a month). Paid plans from $29/user/month billed annually ($34 monthly) up to $89 ($105) for Mixmax Suite.
Comparison table
| Tool | Slack | Sends the follow-up for you | Writes it for you | Stops on reply | Lowest paid price | |
|---|---|---|---|---|---|---|
| autoremind.ai | Yes (Gmail) | Yes (internal) | Yes | Yes | Yes | $4/month |
| Slack /remind | No | Yes | Posts a reminder | No | No | Free with Slack |
| Boomerang | Yes (Gmail) | No | No, reminds you | Respondable helps (paid) | n/a | $4.98/month (annual) |
| FollowUp.cc | Yes (Gmail) | No | Yes | No, you or a template | Yes | $18/month (annual) |
| Mixmax | Yes (Gmail) | No | Yes (sequences) | AI help on some plans | Yes | $29/user/month (annual) |
Which channel to use for what
- Clients, suppliers, anyone outside your company: email. It leaves a written trail and it is where they expect business requests. Invoices especially belong here.
- Teammates: Slack, if that is where they actually read messages. A Slack nudge to a colleague is lighter than a formal email.
- Mixed: if a teammate has gone quiet on Slack for days, an email can carry more weight. Pick the channel the person reads, not the one that is easiest for you.
The Slack vs email reminders breakdown goes deeper on this. If you only need an email tool, the comparison of automated follow-up reminder tools covers more options, including GMass and Saleshandy.
FAQs
Is there one follow-up tool that covers both Slack and email? autoremind.ai covers both: it sends follow-ups to clients and other outside contacts from your own Gmail, and chases people inside your team in Slack, with the same one-sentence setup. Most other follow-up tools are email-only, and Slack's own /remind only posts a reminder, it does not chase someone until they answer.
Can Slack follow up automatically on its own? Partly. Slack's /remind command can post a reminder to you, a person or a channel, and can repeat by day (for example every Monday) but not by hour. It sends the same text every time and does not stop when someone responds.
Is FollowUp.cc still available in 2026? Yes. As of 2026-10-01 FollowUp.cc is a Gmail add-on with reminders, tracking, send later and follow-ups that send automatically if there is no reply. Plans start at $18 a month billed annually, with a 14-day free trial. It does not cover Slack.
Do any follow-up tools write the messages for you? autoremind.ai writes every follow-up from a one-sentence description and makes each one firmer than the last. Mixmax has Smart compose and an AI sequence builder on some plans, and Boomerang has Respondable on paid plans. FollowUp.cc has you write follow-ups or pick a template.
Should I follow up in Slack or by email? Use email for clients and anyone outside your company, and Slack for teammates if that is where they actually read messages. A formal request such as an invoice belongs in email so there is a written trail.
Does autoremind.ai work with Microsoft Teams or Outlook? Not yet. autoremind.ai works with Gmail and Slack today. Outlook support is planned; Microsoft Teams is not supported.
See also: Slack follow-up automation: the complete guide · Slack vs email for business reminders · How to automatically follow up when someone doesn't reply
