Lemwarm vs Reply.io: Cross-Category Comparison

Reply.io's pricing page says email warmup is included with every mailbox. Two questions decide this pairing: how the Reply.io Outlook and Microsoft 365 integration connects a mailbox for cold email sequencing, and what a separate warmup subscription buys on top of warming that is already included.

Lemwarm charges per mailbox, at $29 per email account a month, or $24 on yearly billing, through a network its site describes as "20,000+ healthy domains in 100+ countries". Reply.io's entry plan lists unlimited mailboxes under a fair usage policy. Both vendors therefore meet on the same unit, the mailbox, and the arithmetic below is about what an extra $29 per mailbox buys.

Does Reply.io Integrate With Outlook And Microsoft 365?

Yes. Reply's help article on Outlook and Exchange accounts offers two single-click options: "Outlook" for Outlook and Office 365 mailboxes with IMAP enabled, and "Exchange" for EWS mailboxes on Microsoft servers, where an API is used for receiving instead of IMAP. Mailboxes on private Exchange servers connect through an Autodiscover option. Microsoft's own sending limits then apply to every sequence.

The setup is short. In Reply, open the Email Accounts tab of Settings, click New email account, choose the provider, and sign in to the mailbox; a green dot beside the address means the connection worked. The one trap is IMAP. Reply's article says the Outlook option "will not work if your IMAP is disabled", and that you should ask your administrator to enable it if you cannot reach the setting yourself. For Exchange on a private server, the Exchange (on-premises) option takes the address and password and finds the EWS endpoint with an Autodiscover button.

What Microsoft 365 Allows A Sequence To Send

Connecting the mailbox is the easy half. Microsoft's Exchange Online limits page lists a recipient rate limit of 10,000 recipients per day and a message rate limit of 30 messages per minute on its Microsoft 365 business and enterprise plans, and it says customers who need to send legitimate bulk commercial email "should use third-party providers that specialize in these services". Reply's side of this is a per-mailbox safety setting, "Delay between each email sent", which spaces sends so a sequence stays under the per-minute cap.

Those numbers are ceilings rather than targets. A cold programme on Microsoft 365 runs the way any cold programme should: one message per campaign, no thread replies and no bump steps, spread across several mailboxes at a modest daily volume each, which is where the warming question below comes from.

Why These Two Get Compared

Reply.io and Lemwarm both appear in a cold outbound budget, and they buy different things. A sending platform runs the campaign: the list, the sequencing, the sending schedule and the replies. A warmup tool works on the mailbox underneath it, generating the engagement history that decides whether the campaign reaches an inbox or a spam folder. Neither substitutes for the other.

A dedicated warmup vendor beside Reply.io is a deliberate upgrade rather than a gap-filler, and it should be justified by something the bundled warming does not do rather than by an absence. The two candidates worth weighing are the network the warming runs through and the independence of the reporting, since a platform reporting on the reputation of mailboxes it also sends from is marking its own work.

Lemwarm is lemlist's own warmup product, so anyone weighing it is often also weighing the lemlist alternatives, several of which bundle warming on different terms.

Where Each Tool Fits In A Cold Outbound Run

A cold outbound run at RevenueFlow is built on one message per campaign, no thread replies and no bump sequences, spread across a fleet of mailboxes each sending a modest daily volume. That shape is what makes the warming question sharp: a fleet of low-volume mailboxes only works if every mailbox in it is trusted, and a mailbox with no history is not.

Lemwarm warms through a network of other Lemwarm-connected inboxes rather than through seed mailboxes the vendor owns; its site describes "real inboxes, real replies, no bots" across 20,000+ healthy domains. The Smart plan adds personalised warm-up emails built from your real templates.

Pricing Comparison

Lemwarm Pricing

Source: Lemwarm Pricing

Lemwarm's pricing page carries the dollar figures above in its served HTML and re-renders the same numerals in pounds when the page is opened from the United Kingdom, so quote the currency your invoice will use. It also offers quarterly billing at a 10% saving and says lemwarm is included free with every lemlist plan.

Reply.io Pricing

Source: Reply.io Pricing

Reply.io plan	Monthly / annual	Mailboxes
Email Volume, 1,000 contacts	$59 / $49	Unlimited, fair usage
Email Volume, 10,000 contacts	$179 / $159	Unlimited, fair usage
Multichannel, per user	$99 / $89	5 monthly, 10 annual

Extra mailboxes cost $29 a month each, per Reply's help centre. Email warmup is included with every mailbox.

How Each Side Actually Prices

Reply.io prices its Email Volume plan by active contacts, which its page defines as the unique contacts you can send a first-step email to in a month. The slider runs from $59 a month for 1,000 active contacts to $999 for 100,000 on monthly billing, and from $49 to $899 billed annually, and every step lists unlimited mailboxes subject to a fair usage policy. Multichannel adds LinkedIn, calls and SMS at $99 per user a month with five mailboxes, or $89 billed annually with ten. Agency Core starts from $210 a month, and the AI SDR tier starts from $500 a month billed annually.

Lemwarm prices per email account: $29 a month on Essential and $49 on Smart, falling to $24 and $40 on yearly billing. That per-account unit is the whole story for an outbound team, because the figure that matters is the entry price multiplied by the number of mailboxes being warmed.

What A Two-Tool Stack Costs

Here is illustrative arithmetic for a ten-mailbox setup, invented as a worked example rather than taken from any client, using the vendors' own list prices.

On the Reply.io side, Email Volume at 1,000 active contacts is $59 a month, or $49 billed annually, and it lists unlimited mailboxes, so ten mailboxes fit on one subscription with warming included. On the Lemwarm side, ten email accounts on Essential at $29 each is $290 a month, or $240 at the $24 yearly rate. The warming line is about five times the sending line, for a job the sending line already covers.

The number does not settle the argument, and it frames it correctly: the dedicated vendor has to earn about five times the platform's price, on a fleet where the platform already warms every mailbox.

Does Reply.io Already Include Warmup?

Reply.io's pricing page says email warmup is included with every mailbox, which is about as unambiguous as this category gets. A dedicated warmup vendor alongside it is a deliberate upgrade, and it should be justified by something the bundled warming does not do rather than by the absence of warming.

This is the question that decides whether you are closing a gap or buying an upgrade, and it is worth answering from the vendor's own current page rather than from a feature list that may predate a repackaging.

How To Tell The Warming Worked

Reply rate is the honest measure and it is the slowest one to arrive. Bounce composition moves sooner and says more: a rising share of soft bounces and policy rejections concentrated on one mailbox provider points at reputation, while a rising share of unknown-user bounces points at the list instead. Those are different problems and only the first one is what a warmup tool is for.

Lemwarm's daily deliverability score is the vendor's own answer to the same question, and it is worth reading beside the campaign's numbers rather than instead of them. A vendor dashboard reports its own activity, so a score that improves while replies do not has told you the tool ran rather than that placement changed.

What Warming Will Not Fix

Warming raises the odds that a message is seen. It does nothing about whether the message deserved to be. A warmed mailbox sending a badly targeted list gets the same silence as a cold one, and the engagement ratio the warming was protecting falls anyway once real recipients start ignoring real emails at volume.

Three things sit upstream of both tools and neither vendor sells them. The list has to be right, because relevance is what produces the replies that hold a reputation up. The offer has to be worth answering. And the send pattern has to stay ordinary: one message per campaign, no thread replies, no bump sequences, and a day's volume spread across mailboxes rather than concentrated in one.

On Microsoft 365 the numbers to hold against your plan are Microsoft's: 30 messages per minute and 10,000 recipients per day for each mailbox. Warming does not raise either of them, which is why the volume goes across mailboxes rather than up.

Feature Highlights

Lemwarm Key Capabilities

• Automatic email warm-up across 20,000+ healthy domains in 100+ countries
• Technical setup check and deliverability reports
• Human warm-up emails, and on Smart, warm-up of your real email templates
• Custom deliverability alerts and tips, and a warm-up network tailored to your industry (Smart)
• A daily deliverability score
• Gmail and Outlook connected in one click
• Included free with every lemlist plan

Reply.io Key Capabilities

• Email warmup included with every mailbox
• Live data from 1 billion B2B contacts
• Anti-spam and deliverability suite
• LinkedIn automation at $69 a month per account, calls and SMS at $29
• Integration pages for Office 365, Outlook and Microsoft Exchange
• AI SDR plans from $500 a month billed annually
• 14-day trial

Where The Two Overlap

The overlap is small and it sits entirely on the deliverability side. Lemwarm does one job and does not send campaigns, so the two lists compete on almost nothing that matters to a buyer. Read the difference between them the way it is written: a feature that appears on one vendor's page and not on the other's is a difference in what each chose to publish, not proof that only one tool can do it. Both lists above are taken from the vendors' own pages.

Integration Ecosystem

Lemwarm's site says it connects Gmail and Outlook in one click and that other providers such as Zoho, FastMail and Proton work too. Reply.io has integration pages for Office 365, Outlook and Microsoft Exchange, the last two marked native, and its help articles describe the single-click and Autodiscover routes above.

The shared ground is the mailbox. Both tools attach to the same Outlook or Microsoft 365 account, which is what lets one warm an address while the other sends from it, with no integration work between them.

When To Choose Lemwarm First

Using Both Together

If both are running, split them rather than duplicating. Lemwarm connects to Gmail, Google Workspace, Outlook, Microsoft 365 and SMTP, so any mailbox Reply.io sends through can warm on Lemwarm's network instead of, or alongside, the bundled warming. Putting the dedicated vendor on the newest domains and leaving the bundled warming on the established ones is the arrangement the arithmetic supports.

Watch which Reply.io plan the fleet sits on as it grows. Email Volume lists unlimited mailboxes under a fair usage policy and meters active contacts instead; Multichannel lists five mailboxes on monthly billing and ten billed annually, and Reply's help centre prices extra mailboxes at $29 a month each. Model the plan you will be on in month three, with Microsoft's per-mailbox caps as the limit on each address.

Rolling It Out Without Losing The Reputation

Two house rules matter most once the stack is live. One message per campaign means a prospect who does not reply is re-approached in a fresh campaign with a fresh angle rather than chased down the same thread, and it keeps each mailbox's send pattern closer to ordinary correspondence. Spreading a day's volume across mailboxes does the same for the fleet, and on Microsoft 365 it is also how each address stays well inside 30 messages a minute.

Decision Shortcut

If Reply.io is in the stack and the domains are established, the included warming is doing the job and Lemwarm is an optional upgrade rather than a missing part. If the domains are new, put those specific mailboxes on Lemwarm and give them the four weeks plus two that Lemwarm's own site suggests before the first send. If the mailboxes are Microsoft 365, connect them through Reply's Outlook option with IMAP on, and let Microsoft's 30-a-minute cap and a per-mailbox delay set the pace.

Related Reading

• Best Lemwarm Alternatives in 2026
• Best Reply.io Alternatives in 2026
• Lemwarm vs Warmbox
• Lemwarm vs Mailreach
• Instantly vs Reply.io

If you would rather have this run for you, RevenueFlow books qualified meetings on a pay-per-meeting basis, against criteria agreed in writing before launch, and publishes client results.

Pricing and features are taken from the vendors' own pages. Verify current terms with the vendor before relying on them.