Lemwarm vs Instantly Warm-Up: Price, Pool and Who Each Suits

Lemwarm is cheaper for a single mailbox ($29 a month, $24 on annual billing), while Instantly is cheaper from two mailboxes up, because its $47 Growth plan states unlimited email accounts with unlimited warm-up. Neither has a free plan, and both support Gmail and Outlook. Choose on the price alone and you may pay for a sending platform you never use, so check how you actually send first.

Below are the facts from each vendor's own pricing page, the cost at 1, 5, 20 and 50 mailboxes, who each one suits, and a short section on a free option if you only need warm-up. If you are considering moving off Lemwarm entirely, the Lemwarm alternatives roundup goes wider.

How did we compare them?

We used only what each vendor states on its own pricing and help pages. Lemwarm and Instantly prices were read on 3 October 2026, with trial and pool details re-checked on 4 October 2026. Anything a vendor does not state is marked "not stated" rather than guessed. Prices change, so check before you buy.

We did not run inbox placement tests. A pool size claim tells you how many accounts a vendor says are in its network. It does not tell you where your mail lands. No one in this comparison, us included, can guarantee inbox placement.

Lemwarm is lemlist's warm-up product. Instantly is a cold email platform with warm-up built in. That difference in what you are buying explains most of what follows.

What are the key facts side by side?

The two Instantly pool figures came from two different Instantly pages read a day apart. We report both rather than pick one.

What does each cost at 1, 5, 20 and 50 mailboxes?

Monthly cost, using the cheapest paid plan for each. Lemwarm's annual price is in brackets.

The crossover is at two mailboxes. On monthly billing, two Lemwarm addresses ($58) already cost more than Instantly Growth. On annual billing, two Lemwarm addresses ($48) are about the same; from three onward Instantly is cheaper.

This assumes Instantly's "unlimited email accounts" statement applies to your use without extra limits. The Growth plan has outreach limits of its own, which we did not compare. Read the plan page before you commit, especially if you plan to send a lot through it.

Does a bigger network mean better delivery?

Not on its own. Both vendors quote a network size, and Instantly's is far larger by its own claim. But the number describes how many accounts or domains a vendor says take part. It is not a measurement of where your mail lands.

Three things matter more than the headline figure:

• Who is in the pool. Instantly states its pool is made of its customers' accounts. Lemwarm states "real domains in 100+ countries". Neither page we read publishes how those accounts are screened.
• How varied the peers are. Warm-up looks more natural when your mailbox exchanges mail with different domains and providers, not only with its own colleagues.
• What you measure. A warm-up spam rate tells you how often your warm-up mail was found in Spam by the mailboxes that received it. Watch that number, and your real campaign bounces and complaints, rather than a pool size.

Google's email sender guidelines set the ceiling that matters for Gmail recipients: keep spam complaints below 0.1% and never reach 0.3%. No warm-up network changes that ceiling.

Who should pick Lemwarm?

Lemwarm fits a narrower case well.

You already use lemlist. lemlist seats include Lemwarm. If your team sends through lemlist, its warm-up is already part of the bill, and adding a second tool adds work without clear gain.

You warm one or two addresses. At one mailbox, Lemwarm's $29 (or $24 annual) is the lower price. A founder warming a single sending address pays less than Instantly's platform fee.

You need broad provider coverage on one plan. Lemwarm lists one-click Gmail and Outlook, mentions Zoho, FastMail and Proton, and accepts SMTP. Teams on mixed providers, including Microsoft 365, are covered.

You want a warm-up-only product. Lemwarm is sold per email address as warm-up. You are not paying for a sending platform you may not use.

Where it costs you: every extra address adds $24 to $29 a month. At 20 mailboxes that is $480 to $580, roughly ten times Instantly Growth.

Who should pick Instantly?

Instantly is the stronger value for a team that sends cold email at volume.

You send through Instantly anyway. Growth bundles warm-up for unlimited email accounts. If Instantly is your sending tool, warm-up comes with it at no extra line item.

You run many mailboxes. From two mailboxes up, a flat $47 beats paying per address. Agencies and teams with 20 or 50 sending mailboxes see the biggest gap.

You want to test before paying. Instantly's 14-day trial needs no card and includes warm-up from day one, with stated limits of 250 contacts and 1,000 emails. Note that the account is deleted if you do not upgrade.

You value a large customer pool. Instantly states its warm-up pool is made of its customers' accounts and gives a figure in the millions. If pool size matters to you, its stated number is the larger of the two.

Where it costs you: warm-up is not sold separately on the page we read. If you send from another tool, you pay for a platform to get its warm-up.

Is there a free alternative?

If you only need warm-up, and your mailboxes are not on Microsoft 365, there is a free option. Here are the facts, kept short.

BobWork Email Warm-up is free for up to 10 mailboxes per account, with no credit card and no time limit. Above 10, each mailbox is $5 a month ($3 each from 10 extra, $2 each from 50 extra). For 50 mailboxes that is $120 a month. Full steps are on the pricing page.

What the free option does: each mailbox ramps from 3 to 30 warm-up emails a day, replies go out on about 40% of received warm-up mail, and warm-up mail found in Spam is moved to the Inbox. A mailbox is marked ready for outbound after 7 days of warming, a 7-day spam rate at or under 10%, and at least 30 warm-up emails received.

What it does not do: it does not support Outlook or Microsoft 365, because Microsoft requires OAuth for that connection. Google sign-in shows an "unverified app" notice and spots are limited, so the recommended Gmail route is an app password over IMAP. It is a standalone warm-up tool, with an optional pay-as-you-go Outbound feature ($2 per 1,000 emails) rather than a full outreach platform.

At 50 mailboxes, Instantly Growth ($47) is cheaper than BobWork ($120). If you already send through Instantly, keep its warm-up. The comparison pages for Lemwarm and Instantly warm-up cover switching in more detail.

Do this before choosing

Whichever you pick, the warm-up tool is the smaller part of deliverability. Authentication, list quality and modest daily volume do most of the work. Our Instantly vs Smartlead warm-up comparison covers the other common platform choice.

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