Fyxer vs Superhuman vs an AI in Slack for email follow-ups

What the split actually is

Fyxer is an AI layer inside Gmail that drafts follow-ups you still send, Superhuman is a fast mailbox with reminders and Auto Drafts that never go out on their own, and an AI in Slack for email follow-ups posts the morning list and holds every Gmail send until a person taps.

Founders and operators at companies of 2 to 50 people live in Gmail and Slack. They type I'll send that Friday, or they wait on a reply, and the thread dies because nothing keeps it. The buying prompt collapses three neighboring jobs: a fast inbox, a Gmail-native assistant that drafts the chase, and a hire in Slack that keeps the same open loops. A cadence that sends on its own is a different product.

Superhuman occupies the fast mailbox. Fyxer occupies sorting and awaiting-reply drafts inside Gmail. The prompt then asks for an AI in Slack. Those are neighboring jobs. Silence after send is on how to keep track of emails you're waiting on. A promise you typed is on how to stop forgetting emails you promised. The send gate itself is on the approval-before-send page.

Which job each one wins

Each row names the job, the product that wins it, and why. Superhuman and Fyxer still win the rows they actually win.

What Superhuman is, from its own pages

Superhuman Mail is a fast email client on top of Gmail. Starter is $25 per member per month billed annually, or $30 billed monthly. Business is $33 billed annually, or $40 billed monthly, as of 11 October 2026. Remind Me is H. Reminders default to if no reply. Set regardless if the promise still needs to go out after they write back.

Auto Reminders ship on every plan. Superhuman AI detects that a follow-up is needed from the latest outgoing message if no reply has been received. You can also remind on every external send, or turn them off. Auto Drafts are on Business and Enterprise. They write follow-ups about an hour before a reminder returns, and responses when mail needs a reply. They appear as ordinary drafts and are never sent automatically. If a placeholder is still empty when you hit send, Mail alerts you.

Email Assistant puts Auto Labels, Auto Archive, Auto Drafts, and Auto Reminders inside the existing Gmail inbox, with no new app required. Auto Labels are Respond, Waiting, FYI, Notifications, Promotions, or News. Waiting is you are waiting to hear back. That is silence after send, not I'll send that Friday in the body.

Superhuman's own pages do not describe a Slack hire that keeps Gmail promises. The mailbox is the product. Work across apps with a send gate is a neighboring job, on Lindy vs an AI employee in Slack.

What Fyxer is, from its own pages

Fyxer plugs into Gmail. It labels mail that needs a reply, drafts in your voice, and tracks sent threads that got no reply. Those threads stay in Sent until a wait you set has passed, then they are flagged Awaiting reply or To follow up and a follow-up draft is created. Fyxer never sends drafts automatically; you always review and approve. The pricing FAQ is the same line: it does not send emails on your behalf; you decide what gets sent.

Pro is $37 per person per month billed annually, or $49 billed monthly. Team is $64 billed annually, or $99 billed monthly, with a two-seat minimum. Automatic labeling and replies drafted in your tone start with Pro. Free is a weekly email briefing, dashboard actions updated daily, and 400 credits a month. Pro's follow-up list refreshes every hour.

Fyxer in Slack is a tagged assistant, not a send-gate hire. Address @Fyxer in a channel or DM. It can search private messages and DMs, send a Slack message on your behalf, schedule a message for later, and pull calendar. Flows can deliver a morning briefing, an action-item roundup, or a commitments-first summary to a Slack DM or channel, to email, or in-app. Fyxer says Flows are rolling out gradually, so availability varies.

A Slack message on your behalf is a different gate from an email draft you still send. Put that in writing before you let @Fyxer send in a shared channel.

What the AI in Slack job is

The Slack job is not a faster inbox, and it is not a tagged assistant that answers when you remember to @mention it. It is a hire next to the rest of the work that keeps every promise made in a Gmail thread, and every thread waiting on a reply, then puts the list where you will actually open it.

Operators already say email reminders go to die, and a generic Slack task list gets muted. A morning line that names the person and the reason is the list that gets done. The same wait is often an email and a Slack ping. Two tools, two lists, and the warm intro still goes cold.

Concrete is an AI employee that works in existing Slack channels and reads Gmail alongside them. It keeps every promise made in a thread, and every thread waiting on a reply, as a follow-up. Each morning it nudges the owner. It drafts the follow-up as a Send / Edit / Skip card in Slack. A Gmail send needs the same tap. There is no auto-send mode. Follow-ups survive reboots. It is in design-partner preview. The send gate in Slack itself is on the approval-before-send page. An assistant that drafts follow-ups and cannot send without a tap is on the draft-only page.

The caveat that should decide the shortlist

The failure operators name first is an AI that sends the follow-up on its own. A prompt that says draft only is not a send gate: people have watched a bot email the team after they told it not to. Worst case with a draft is you delete it. Worst case with auto-send is you explaining the email on Monday.

Fyxer never sends email drafts automatically. In Slack it can send a Slack message on your behalf. Superhuman Auto Drafts wait for you to hit send, and still alert if a placeholder is empty. Lindy's follow-up bumps land in your drafts folder. Anything with outside impact waits for approval, and Always allow turns that gate off. Guardrails apply in shared Slack threads only, not in the web app, Slack DMs, iMessage, or SMS.

A second caveat is where the list lives. Superhuman returned reminders live in the mailbox. Fyxer follow-up drafts live under Awaiting reply. Gmail Nudges sit at the top of the inbox. An AI in Slack posts the morning list next to the rest of the work. Fund the surface you will actually open. A third caveat is the promise versus the silent thread. Most inbox tools watch silence after send. I'll send that Friday in the body is a neighboring job.

What each one costs (October 2026)

Every figure below is from the vendor's own pricing page or docs, read 11 October 2026. Quote-only stays quote-only. Concrete has no public price.

A practical setup for a 2-to-50 person shop

This is the boring version that holds when the founder still owns the one-to-one threads. Pin it before the next warm intro goes cold in Sent.

• Name the job. A fast inbox is Superhuman. Gmail-native sorting and awaiting-reply drafts are Fyxer. Free snooze is Gmail. A hire in Slack that keeps Gmail promises, with send as a tap, is a different product. Fund the leak you actually have.
• Name the gate. Send is a tap on the exact text. Edit rewrites it. Skip drops it. Always allow, a Slack message on your behalf, or a prompt that says draft only is a different setup.
• Keep client-facing send on the gate. Lookups, labels, and internal notes can run. Anything a prospect, investor, or customer will see waits. If the vendor offers Auto or Always allow, leave it off on send.
• Put the morning list where you will see it. A follow-up that only lives in Sent is easy to skip. Superhuman returned reminders and Gmail Nudges live in the mailbox. Fyxer drafts live under Awaiting reply. Concrete posts the list in Slack.
• Keep Gmail and Slack on the same list. The same wait is often an email and a Slack ping. Two tools, two lists, and the intro still goes cold. One follow-up that survives both is the job.
• Separate the chase from a sequence. A follow-up draft on a warm intro is one-to-one. A cadence that sends without a tap is a different product. Draft the chase. A person still sends.