How reply detection works

Every campaign sends from your own Gmail, so every reply lands in your own Gmail. ColdMerge does not hold your mail. It watches for replies to the threads it started, records the fact that someone answered, and stops following up with that person.

This page explains how that works, what it deliberately does not do, and where it can miss.

What ColdMerge looks at

ColdMerge keeps a standing subscription to each connected mailbox, so a reply is usually noticed within moments of arriving. A periodic safety check runs behind it and re-reads the mailbox anyway, so detection never depends on one notification arriving.

Here is the part that matters most:

That is a design rule, not a courtesy. A message is considered only if its Gmail thread matches a thread ColdMerge sent on your behalf. Nothing else is ever looked at.

And even for the replies it does record, ColdMerge stores no message body. It keeps who replied, which thread, when, and a one-line preview. The body stays in Gmail, which is where you read it and where you answer from.

You reply in Gmail, not in ColdMerge

There is no inbox inside ColdMerge. Reply detection tells you that someone answered and stops the follow-ups. Reading and answering happen in your own Gmail, one click away from the alert or the message row.

The three kinds of inbound message

Anything that arrives on one of your campaign threads is sorted into exactly one of three buckets, checked in this order.

Kind	What it is	What it stops
Bounce	A delivery failure notice from a mail server	A permanent bounce stops every live sequence for that contact and suppresses them
Auto-reply (out of office)	An automatic acknowledgement	Nothing. Follow-ups carry on
Human reply	A person wrote back	That campaign’s follow-ups to that person

When a message is genuinely ambiguous, ColdMerge treats it as a human reply. That is the safe direction: it is much better to stop following up with someone who may have answered than to keep emailing someone who did.

Bounces: permanent versus temporary

Only a permanent failure counts. Mail servers report failures with a status code: a 5.x.x code means the address is genuinely gone, and a 4.x.x code means “not right now, try later”. A 4.x.x is dropped and changes nothing, because the address may be perfectly good.

A permanent bounce does three things: it stops every live sequence that contact is in, it adds them to your suppression list with the reason bounce, and it marks them undeliverable.

What a reply stops, exactly

This is the distinction people get wrong most often.

A human reply stops one campaign. It ends the follow-ups from that campaign to that person. If the same contact is in a second campaign, that second campaign keeps going.
A suppression stops everything. An unsubscribe, a permanent bounce, or a manual entry stops every live sequence for that contact across your whole account.
An auto-reply stops nothing. An out-of-office is not an answer.

The stop is checked twice: once the moment the reply is classified, and again in the last seconds before a follow-up is handed to Gmail. A reply that lands while a follow-up is queued still stops it.

See follow-up sequences for how the follow-ups themselves work.

Where detection can miss

ColdMerge watches the inbox. That is the whole scope, and it has one honest consequence.

This is a known and accepted limit, not a fault being worked around. It is worth knowing about, because a real reply landing in Spam is the one case where a sequence keeps going when it should have stopped. There is no setting that widens the scope. If you make an occasional pass over the sending mailbox’s Spam folder and find a real reply there, stop that person’s follow-ups yourself rather than relying on the rescue being noticed.

There is one more narrow case. If a first email goes out but ColdMerge never learns its Gmail thread, that contact receives the first email and nothing further. No follow-ups are ever queued for them. That is deliberate: ColdMerge does not follow up on a conversation whose replies it cannot see.

Reply alerts

Alerts live in Settings, then Notifications. The screen lists each alert this product raises and how it reaches you.

The Replies row is the one you choose. It offers three settings:

Setting	What happens
Email, one per reply	You get an email the moment each reply is detected
Email, daily digest	You get one email a day listing every reply since the last one
Bell only	No email. The reply still shows in the app

Pick one and select Save preferences. Reset appears while you have an unsaved change.

Two rows below it are marked Always on rather than hidden, so you are not hunting for a switch that does not exist:

Campaign paused, if sending auto-pauses because a bounce rate climbed too high.
In-app bell, every reply and alert, shown the moment it lands.

What a reply alert contains

A single-reply email is subject-lined New reply from the contact’s address, plus the campaign name when there is one. Inside, it carries who replied, which campaign, when, a one-line preview, and a button that opens the thread in Gmail.

The digest carries the same fields for each reply, in one list.

Reply alerts carry no unsubscribe link, because they are not marketing. They are an alert you turned on, so they point back at the setting that controls them instead.

Where replies show up

The bell in the app, immediately.
The reply rate on Analytics, which is the headline number ColdMerge leads with.
The campaign’s own progress, where a reply removes that person from the remaining follow-ups.