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Warmerly Warmup Inbox

One-to-one · Campaign sending

Campaign sending

One row, in depth: what each tool does, the verified numbers, and who each suits.

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Warmup Inbox details read from its pricing page, home page, product pages, API page, integrations pages, help centre, legal pages and status page on 21 October 2026.

Warmerly

Sequences with email, wait, LinkedIn and branch steps, 13 pre-launch checks and one reply inbox; no cap on sends on paid plans.

Warmup Inbox

Sequences with A/B tests, optional verification and a unified inbox, up to 10,000 contacts a campaign; no open tracking.

The short answer

Campaign sending, in one look.

Both send campaigns from the mailboxes they warm, and the differences are in what a campaign can do. Warmerly sequences mix email, wait, LinkedIn and branching steps, run 13 kinds of pre-launch check, and are not metered on paid plans. Warmup Inbox sequences have A/B tests that pick winners on replies, optional EmailListVerify verification, a unified inbox and up to 10,000 contacts a campaign, and it deliberately has no open tracking. Warmup Inbox says a campaign can only send from an inbox that is already warming, which Warmerly does not require. Last checked 21 October 2026.

WarmerlyWarmerly ahead on this row

Sequences with email, wait, LinkedIn and branch steps, 13 pre-launch checks and one reply inbox; no cap on sends on paid plans.

Warmup Inbox

Sequences with A/B tests, optional verification and a unified inbox, up to 10,000 contacts a campaign; no open tracking.

The picture

Drawn side by side.

What each covers

From mailbox to what happens next

WarmerlyWarmup Inbox

Warmerly

WarmupSequence with LinkedIn13 launch checksSendOne reply inbox

Warmup Inbox

Warming inbox onlySequence with A/B testsOptional verificationSendUnified inbox

Warmup Inbox sends campaigns only from inboxes that are warming and has no open tracking.

On screen

What it looks like.

Campaigns. A campaign list, its sequence and the pre-launch checks, sample data — Campaigns. A campaign list, its sequence and the pre-launch checks.Warmerly app, sample data.

Campaigns. A campaign list, its sequence and the pre-launch checks, sample data — Campaigns. A campaign list, its sequence and the pre-launch checks.Warmerly app, sample data.

How Warmerly does it

Warmerly, in detail.

A sequence builder with email, wait, LinkedIn and branching steps, a readiness check before launch, per-mailbox pacing with a reputation brake, and one reply inbox for email and LinkedIn.

01

Steps in one sequence

A sequence is made of email steps, wait steps, LinkedIn connection and message steps, and condition steps that branch on opened, clicked, replied or timeout. A list editor or a drag-and-drop canvas builds them, and only the canvas can build branches.

Warmerly product, checked 21 October 2026

02

Checks before Start

The readiness table lists 13 kinds of check: 7 that block, such as no usable step, no sender, no queued leads or an unknown merge tag, and 6 that warn, such as no postal address, a sender whose DNS check is warn or fail, or spam-style copy. Warnings need one acknowledgement.

Warmerly product, checked 21 October 2026

03

Pacing and the reputation brake

Each mailbox has a daily campaign limit, 30 by default, and a minimum wait between sends of 10 minutes, stretched by a random 0 to 100%. From a 2 per cent seven-day bounce rate the cap is cut to 0.75, at 3 per cent to 0.5 and at 5 per cent to 0.25. At 7 per cent the mailbox is paused.

Warmerly product, checked 21 October 2026

04

A ramp for young mailboxes

The campaign ramp starts at 3 emails per mailbox on day 1 and adds 1 a day to 15 by default, counting only sending days. It is on by default for a campaign whose mailboxes have under 14 days of warmup.

Warmerly product, checked 21 October 2026

05

Unsubscribes and suppression

Campaign emails carry List-Unsubscribe and one-click headers and a footer link by default. Unsubscribes go on a workspace-wide suppression list checked before every send, and email suppression also stops a lead's LinkedIn steps. Open tracking is off by default.

Warmerly product, checked 21 October 2026

06

Replies and the inbox

Connected mailboxes are synced for new mail every five minutes. A reply is matched through the mail's reply headers, bounces and automatic replies are classified separately, and a genuine reply stops the lead's sequence by default. Replies land in one inbox with LinkedIn replies.

Warmerly product, checked 21 October 2026

07

What is capped

Sending is not metered on paid plans. Free is capped at 100 campaign sends a month. Leads per campaign are 500 on Free, 2,500 on Starter, 25,000 on Growth and 100,000 on Agency, and Starter runs 5 active campaigns.

Warmerly product, checked 21 October 2026

How Warmup Inbox does it

Warmup Inbox, in detail.

A campaign product described as sharing its plumbing with warmup: sequences, A/B testing, optional verification, four ways to import contacts and a unified inbox, with no open tracking.

01

Only warming inboxes can send

The cold email sequence page says a campaign can only send from an inbox that is actively warming, and that the restriction is deliberate rather than technical. It also says warmup volume does not drop when a campaign runs, because they use the same inbox at the same time.

warmupinbox.com/product/cold-email-sequence · read 21 October 2026

02

Sequences that branch

The page describes emails, waits and conditions, with branching on whether someone replied, clicked or bounced, and actions to stop, move on, mark interested or notify the team. There are six templates, and every one stops sending to a contact when they reply.

warmupinbox.com/product/cold-email-sequence · read 21 October 2026

03

A/B testing decided on replies

Any email can have two variants with a set split. Reply and bounce rates are reported per variant per step, each contact keeps one variant, and the winner is applied from the campaign list with pending sends switching without a restart. It picks winners on reply rate.

warmupinbox.com/product/cold-email-sequence · read 21 October 2026

04

No open tracking, on purpose

Its FAQ says it does not track opens, and that this is deliberate: open tracking loads a remote pixel that filters use as a signal. Campaign analytics report sends, replies and bounces, and update every two hours.

warmupinbox.com/product/cold-email-sequence · read 21 October 2026

05

Verification is a switch

The FAQ says verification runs through EmailListVerify before the campaign starts sending, if you turn it on, and that invalid addresses are flagged rather than removed. The page also says invalid contacts are excluded for you automatically.

warmupinbox.com/product/cold-email-sequence · read 21 October 2026

06

10,000 contacts a campaign, four ways in

A campaign holds up to 10,000 contacts. You can import a saved list, upload a CSV with column mapping, paste rows or add contacts by hand. At launch you choose senders, a send window and a daily limit; no default or maximum daily limit is stated.

warmupinbox.com/product/cold-email-sequence · read 21 October 2026

07

A unified inbox

One inbox holds every reply, with filters for campaign, mailbox, tag, unread and bounced, and search by name or address. A reply goes out from the original mailbox in the same thread. Interested leads can trigger an email alert.

warmupinbox.com/product/cold-email-sequence · read 21 October 2026

What Warmup Inbox does not say

We looked, and found no statement on these. That is about its published pages only, not about the product.

A default or maximum daily sending limit for a campaign
How unsubscribes are handled in campaigns; its Anti-Spam Policy says customers must offer a working opt-out and honour it within 10 business days
A cap on campaigns, contacts in total or sends a month by plan
Whether the sequence tool is on Basic only as a listing, since the pricing page says outreach sequences under Basic
LinkedIn or WhatsApp steps; the pricing and sequence pages mention neither
A published pre-launch check or a rule that stops a campaign on bounces

Where the sources disagree

We report each version rather than pick one.

The sequence page says invalid contacts are excluded for you automatically, and its FAQ says invalid addresses are flagged rather than removed.
The sequence page says verification is one switch at launch, and its feature list says to clean the list with EmailListVerify before the first email goes out.
The pricing page lists outreach sequences under Basic, while its comparison pages describe campaign sending as part of the product with no plan named.

The numbers

Only what we could verify.

Campaign sending: Warmerly and Warmup Inbox side by side. Warmerly is in the first column.
Measure	Warmerly	Warmup Inbox
Campaign sending	Sequences with email, wait, LinkedIn and branch steps, 13 pre-launch checks and one reply inbox; no cap on sends on paid plans.	Sequences with A/B tests, optional verification and a unified inbox, up to 10,000 contacts a campaign; no open tracking.
Contacts per campaign	500 Free, 2,500 Starter, 25,000 Growth, 100,000 Agency	Up to 10,000
Campaign sends	Not metered on paid plans, 100 a month on Free	No limit stated
Daily limit per mailbox	30 by default	You set it, no default stated
Step types	Email, wait, LinkedIn, condition	Emails, waits, conditions
A/B winner chosen on	Replies, falling back to opens	Reply rate only
Open tracking	Off by default	None, by design
Verification	5,000 a month on Starter, built into the plan	EmailListVerify, optional switch
Launch checks	13 kinds, 7 block and 6 warn	Not stated

In practice

What it means for you.

Our reading of the facts above. Not a promise, and not the only reasonable reading.

1

The shape of the two is similar

Both tie campaigns to the mailboxes they warm, branch on replies, stop on a reply, hold replies in one inbox and run A/B tests. Warmerly adds LinkedIn steps and a published readiness check, and Warmup Inbox adds content warmup and a cap of 10,000 contacts a campaign.

2

No open tracking is a choice to understand

Warmup Inbox leaves opens out on principle. Warmerly turns them off by default but lets you turn them on, and falls back to opens for a winner only if there are no replies. If you rely on opens for decisions, ask yourself which side you want to be on.

3

Warming first is enforced there

Warmup Inbox only lets a warming inbox send a campaign, which is a safety rule you may like. Warmerly lets any connected mailbox send and uses a ramp and a pre-launch warning when a sender's DNS fails or when more than five senders share a domain.

4

Check the contact numbers against your list

10,000 a campaign on Warmup Inbox sits between Warmerly's Starter (2,500) and Growth (25,000) limits. Warmerly's active prospect cap is a separate, workspace-wide number: 5,000 on Starter, 50,000 on Growth. Neither side's limit is the cap on how many emails a mailbox can send in a day.

5

Unsubscribes need your attention on both

Warmerly adds headers and a footer link by default and suppresses unsubscribes across the workspace. Warmup Inbox's sequence page does not mention unsubscribes, and its Anti-Spam Policy puts a working opt-out on the customer. Whichever you use, set it up before launch.

Who it suits

Pick the one that fits.

Warmerly

Warmerly is the better fit if

You want LinkedIn steps in the same sequence as email
You want a readiness check that blocks a launch with no sender or no step
You want a reputation brake that slows or pauses a mailbox on bounces
You want email and LinkedIn replies in one inbox
You want campaign sends unmetered on a paid plan

Warmup Inbox

Warmup Inbox is the better fit if

You want content warmup for the first email of a campaign
You want a campaign to send only from an inbox that is warming
You want to apply an A/B winner in one click from the campaign list
You want to import contacts four ways, including pasted rows
You want no open tracking at all

Questions

How many contacts can a campaign hold?

Warmerly allows 500 on Free, 2,500 on Starter, 25,000 on Growth and 100,000 on Agency. Warmup Inbox allows up to 10,000.

How many campaign emails does Warmerly send a day per mailbox?

30 by default. Warmup Inbox lets you set it and states no default.

Does either track opens?

Warmerly has open tracking off by default. Warmup Inbox has none, by design.

How does each choose an A/B winner?

Warmerly uses replies and falls back to opens. Warmup Inbox uses reply rate only.

Does Warmup Inbox need a warming inbox to send?

Yes, it says a campaign can only send from an inbox that is already warming. Warmerly does not require this.

Sources

Warmup Inbox pages were read on 21 October 2026. Plans and wording change, so check the vendor's own page before you decide. Warmerly details come from the product as it runs today.

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