Top 5 Email Warm-Up Tools in 2026: Price, Pools, Limits

If you want the top 5 email warm up tools in 2026, choose by your hard constraint: free warm-up, Outlook support, stated daily volume, or an outreach bundle. Ignore that constraint and you may buy the wrong pool. This guide compares five tools by price, pool type, providers, volume and metrics, including the free warm-up tool.

How were the five selected?

This list uses five buying criteria: free plan, pool type, provider coverage, stated daily volume and metric transparency.

For BobWork Email Warm-up, the facts come from our own product behaviour. For the other tools, prices and feature claims were read on 3 October 2026 from each vendor’s pricing page. Check before you buy, because prices and plan names change.

BobWork appears first because it is the only permanent free plan in this comparison, supports up to 20 mailboxes per account and offers a shared network or a private pool per account. Its limits: a private pool needs at least two mailboxes, Outlook is not supported yet, and Google may show an unverified-app notice.

The other four picks were included because their pricing pages state broad provider coverage, clear daily warm-up limits, Outlook support, or bundled outreach value. Where a vendor does not state a number on its pricing page, this guide says so.

For context on pool design, read our guide to private warm-up pools vs public networks. If you are warming a first mailbox, check the day-by-day warm-up timeline before choosing any tool.

What are the top 5 email warm up tools?

This table shows the main trade-off. BobWork is the only permanent free option here, but it does not support Outlook. Warmup Inbox and MailReach have the lowest stated paid per-mailbox prices in this list. Mailwarm costs more but states clear Starter volume. Instantly is different because warm-up is bundled into an outreach platform.

Do not treat shared network size as an inbox placement guarantee. A larger network can make setup easier if you own one mailbox. It also means your mailbox exchanges warm-up mail with strangers’ mailboxes.

A private pool avoids stranger inboxes, but you need enough of your own mailboxes to create exchange patterns. BobWork offers both: the shared network is the default and a private pool (at least two mailboxes) is a switch per account.

Which tool fits your constraint?

BobWork Email Warm-up

BobWork Email Warm-up is free, requires no credit card, has no time limit and supports up to 20 mailboxes per account.

Pick BobWork if you want free warm-up with a choice of pool model. By default your mailboxes warm in the shared network; switch the account to Private pool and only your own mailboxes write to each other. Free forever plus that choice is the strongest reason to choose it under this method.

The default ramp starts at 3 emails per day, adds 2 per day and caps at 30 per day. You can edit the cap per mailbox up to 100. Weekends run at 30%. Sends are spread between 09:00 and 18:00 in the mailbox’s own time zone.

The engine adds randomness every 15 minutes. A pair never writes to each other twice within 3 hours. Peers on a different domain or provider are picked twice as often.

The limits matter. Outlook and Microsoft 365 are not supported yet because Microsoft requires OAuth. Gmail and Google Workspace can connect with Google sign-in, but Google shows an unverified-app notice because we have not done the CASA audit.

You can also use IMAP with an app password where your provider supports it. Zoho works through the Zoho Mail API with a Self Client code, including on the free plan. Zoho can also use IMAP on Mail Lite and above.

BobWork works best when you want control, privacy and no subscription. It is less suitable if you only own one mailbox or need Outlook today. For setup details, see how the warm-up engine behaves or the Gmail warm-up guide.

Warmup Inbox

Warmup Inbox’s cheapest paid plan is $19/month monthly or $15/month annually per inbox, with a 7-day no-card trial and no free plan.

Pick Warmup Inbox if you want a paid shared network with broad provider coverage and Outlook support. Its pricing page lists Gmail, Workspace, Outlook, Microsoft 365, Yahoo, Zoho, ProtonMail, Fastmail, iCloud, AWS SES, Mailgun and any SMTP.

The Basic plan states 75 warm-up messages per day and replies up to 25%. Higher plans state 250/day on Pro and 1,000/day on Max. Those clear volume numbers make budgeting easier than tools that do not state per-mailbox volume.

The trade-off is pool type. Warmup Inbox uses a shared network described as “30,000+ real human inboxes”. That may suit users with one mailbox, but it is not a private pool.

MailReach

MailReach’s cheapest paid price is $19.50 per mailbox per month on monthly billing, with a 20% annual discount and no free plan.

Pick MailReach if you want a paid per-mailbox warm-up tool with a stated volume limit and wide SMTP coverage. Its pricing page says up to 100 warming emails per day.

Provider coverage is broad. MailReach lists any SMTP, including Gmail/Workspace, Outlook/O365, Zoho, Brevo, Mailjet, Mailgun, SendGrid, SES, Sparkpost, Ionos and OVH. That makes it a practical shortlist option for teams using SMTP providers, not only Gmail or Outlook.

The limit is again the shared network model. The pricing page describes a MailReach network of Workspace/O365 inboxes, “30k+”. If you need a private pool, that is not the same structure.

Mailwarm

Mailwarm’s Starter plan is $69/month for 1 mailbox, with up to 50 warm-up emails and 50 replies per day, and no traditional free trial.

Pick Mailwarm if you want a managed paid pool and you value a clearly stated Starter volume. Its pricing page states 50 warm-up emails plus 50 replies per day on Starter. Growth is $159 for 3 mailboxes and 200/day. Scale is $479 for 10 mailboxes and 500/day.

Mailwarm lists Google Workspace/Gmail, Microsoft 365/Outlook and other SMTP platforms. Yahoo, Zoho, AWS, SendGrid and Mailgun are named.

The main limit is price per included mailbox. Starter covers one mailbox at $69/month. That may be fine for one important mailbox, but it becomes expensive if you are warming many senders.

Instantly

Instantly’s cheapest listed plan here is the $47/month Growth outreach plan, which bundles “unlimited email accounts” and “unlimited warm-up”; no permanent free plan is stated.

Pick Instantly if you want outreach software where warm-up is part of the stack. It is not priced like a standalone per-mailbox warm-up tool. The relevant plan is an outreach plan, not just a warm-up subscription.

Instantly lists Google Workspace and Microsoft Outlook. Its pool is described as Instantly customer accounts, “1,000,000+”. That may suit teams already using Instantly for campaigns.

The limit is metric clarity for this comparison. Daily warm-up volume per mailbox is not stated on the pricing page. If your decision depends on exact daily warm-up volume, ask before paying.

Which should you pick?

If you compare only headline price, BobWork is the $0 option. If you need Outlook today, remove BobWork from the shortlist because it does not support Outlook yet. The right answer depends on the constraint you cannot change.

For many cold outreach teams, the constraint is not warm-up volume. It is safe sending volume. A typical starting point is to keep real outreach at 30–50 emails per day per mailbox, then add mailboxes rather than pushing one inbox too hard.

Warm-up does not make aggressive sending safe. If you are choosing between private and shared pools, start with risk tolerance. A private pool gives more control but needs more of your own inboxes. A shared pool gives instant peers but involves stranger mailboxes.

Our explainer on email warm-up networks covers that trade-off in more depth.

What must be fixed first?

Warm-up should not be your first fix if the domain is misconfigured. SPF, DKIM and DMARC need to pass before you judge any warm-up tool. Gmail and Yahoo both publish sender requirements for authentication and complaint control.

Google’s sender guidelines say spam complaint rates should stay under 0.1% and never reach 0.3% or higher. Read the current source in Google’s email sender guidelines. Yahoo also publishes sender requirements on the Yahoo Sender Hub.

DMARC is defined in RFC 7489. You do not need to memorise the RFC, but you should know whether your domain has a DMARC record and what policy it uses.

BobWork checks SPF, DKIM and DMARC daily by DNS and shows results per domain. The DKIM selector search includes common selectors such as google, zmail, default, selector1, selector2, k1, s1, mail, dkim, lark, feishu and zoho.

You can also test records directly with the SPF checker, DKIM checker and DMARC checker.

A healthy warm-up pattern still needs normal-looking sending. BobWork sends plain text, no links, no images and first-name greetings. About 40% of received warm-up mail gets a reply, and threads end after 3 messages.

Warm-up mail found in Spam is moved to Inbox, marked read, labelled “Warm-up” and archived after 24 hours. The free pool does this rescue step automatically for its own warm-up mail.

That rescue action is limited. Only mail carrying the engine’s own hidden header is touched, or for Zoho API senders, a known subject. Real mail is never read, moved or answered.

How should you shortlist?

Use this checklist before you create an account anywhere. It prevents the common mistake of buying a warm-up plan before knowing whether your mailbox, domain and campaign volume can use it.

For BobWork, readiness is measured by three conditions: 14+ days warming, 7-day spam rate at or below 3%, and at least 30 warm-up emails received. The spam rate is the share of a sender’s warm-up mail that receiving mailboxes found in Spam over 7 days.

That metric is direct because it comes from the receiving mailbox. BobWork does not use third-party seed lists. The health score runs from 0 to 100: Healthy is 85 or higher, Watch is 60–84, At risk is below 60, and Blocked means login or permission failed.

Shared-network tools may show different dashboards. Compare what they measure before comparing scores. A “health” label is only useful if you know whether it reflects spam placement, authentication, sending consistency, replies, or another input.

A sensible path is simple. Fix authentication, warm for 14 days on an existing domain or 3–4 weeks on a new one, keep real outreach at 30–50 emails per day per mailbox, and add mailboxes instead of forcing more volume through one sender.

During campaigns, keep warm-up around 10–15 per day. If your constraint is free warm-up, start with BobWork Email Warm-up. It is free, offers a shared network or a private pool, and is capped at 20 mailboxes per account. Remember the limits: no Outlook yet, two or more mailboxes for a private pool, and a Google unverified-app notice until the CASA audit is done.

Frequently asked questions