Warmup Inbox Alternative: Free Warm-Up vs $19 per Inbox

BobWork is the free Warmup Inbox alternative for teams that want up to 20 mailboxes, a shared network or private pool, and a 3→30 emails/day default ramp instead of paying $19 per inbox for 75/day. If you ignore price, pool type, or Outlook support, you may switch to the wrong tool. This comparison shows where each option fits.

Warmup Inbox and BobWork Email Warm-up both help a cold or unstable mailbox build steadier sending activity before real outreach. The main difference is not only price. Both use a shared network; BobWork also lets you switch an account to a private pool, so only your own mailboxes write to each other.

If this is your first warm-up project, read the first-time warm-up timeline before you change tools. Warm-up does not replace SPF, DKIM, DMARC, low complaint rates, clean lists, or conservative sending. It only supports a steadier mailbox pattern.

Prices were read on 3 October 2026 from the vendor's pricing page; check before you buy.

How do they compare?

Use this table for the short version. Warmup Inbox facts come from its pricing page as read on 3 October 2026. If a detail was not shown there, it is marked as not stated.

The biggest price difference appears as soon as you add more than one mailbox. Warmup Inbox charges per inbox. BobWork is free for up to 20 mailboxes in one account.

The bigger product difference is pool design. Warmup Inbox gives you access to a shared network. BobWork gives you a shared network by default and a private-pool switch per account; in private mode nobody else's inbox receives your addresses.

The private mode has one requirement: you need at least 2 mailboxes. With one mailbox, stay on the shared network.

Volume also differs. Warmup Inbox Basic lists 75 warm-up messages per day. BobWork starts at 3/day, adds 2/day, and reaches 30/day by default. During active campaigns, we recommend keeping warm-up around 10–15/day and real outreach around 30–50/day per mailbox.

For sender requirements, use primary provider documentation rather than vendor blog claims. Google publishes bulk sender guidance, including keeping spam complaint rates below 0.1% and avoiding 0.3% or higher in Postmaster Tools. See Google's email sender guidelines. Yahoo also publishes bulk sender guidance in its sender best practices.

When is Warmup Inbox better?

Choose Warmup Inbox if you use Outlook or Microsoft 365. BobWork does not support those mailboxes yet. If your sending stack is Microsoft-based, Warmup Inbox is the usable option today.

Choose Warmup Inbox if you want a shared network by design. Its pricing page describes a shared network of “30,000+ real human inboxes.” That can help if you have one mailbox or want warm-up exchanges with outside inboxes.

Choose Warmup Inbox if you specifically want 75 warm-up messages per day on the cheapest paid plan. BobWork's default cap is 30/day, although the cap can be edited per mailbox up to 100.

Choose Warmup Inbox if you rely on providers it names directly and BobWork does not, such as ProtonMail or Fastmail. BobWork supports any IMAP+SMTP mailbox, but named-provider coverage is not identical.

Choose Warmup Inbox if your team prefers a paid vendor, per-inbox billing, and a defined 7-day evaluation window. BobWork is free with no time limit, so there is no trial window to manage.

The fair summary: stay with Warmup Inbox when Outlook support, shared-network reach, or 75/day Basic volume matters more than a free plan.

When is BobWork better?

BobWork is stronger when your constraints are cost, privacy, and control across several supported mailboxes.

The free plan has no credit card, no time limit, and supports up to 20 mailboxes per account. That matters if you manage small outbound systems, test domains, or several sender identities.

The pool is shared by default, and any account can switch to a private pool where your mailboxes only warm each other. If you want the mechanics behind that model, read how an email warm-up network works.

The engine uses a fixed ramp. It starts at 3 emails/day, adds 2 per day, and caps at 30/day by default. Weekends run at 30%. Sends are spread across 09:00–18:00 in the mailbox's own time zone, with randomness decided 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. About 40% of received warm-up mail gets a reply, and threads end after 3 messages.

The content is plain office-style text. It uses first-name greetings, no links, no images, and no HTML. That keeps warm-up mail from looking like a fake marketing campaign.

Spam rescue is narrow. Warm-up mail found in Spam is moved to Inbox, marked read, labelled Warm-up, and archived after 24 hours. Only mail carrying the engine's own hidden header, or a known subject for Zoho API senders, is touched. Real mail is never read, moved, or answered.

BobWork also checks SPF, DKIM, and DMARC daily through DNS and shows results per domain. You can also test records before connecting with the SPF checker, DKIM checker, and DMARC checker.

For Gmail and Google Workspace, BobWork can connect through Google sign-in with the gmail.modify scope, or through IMAP with an app password. Google may show an unverified-app notice because BobWork has not completed the CASA audit. Google documents app passwords in its Google Account help.

For Zoho Mail, BobWork can use the Zoho Mail API through a Self Client code, including on the free plan, or IMAP on Mail Lite and higher. For Yahoo and iCloud, it uses IMAP with an app password. Yahoo documents app passwords in its Yahoo Account help.

If you want the exact sending pattern before you connect anything, the engine behaviour page explains the ramp, limits, timing, replies, spam rescue, and readiness rules.

What does each mailbox cost?

Price is the clearest difference once you manage several mailboxes. Warmup Inbox charges per inbox. BobWork is free up to 20 mailboxes per account.

This table uses Warmup Inbox's listed Basic price: $19/month when paid monthly, or $15/month when paid annually. It excludes taxes, future pricing changes, and any discounts beyond the listed annual price.

For one mailbox, the monthly difference is $19. For 5 mailboxes, it is $95/month. For 20 mailboxes, it is $380/month on monthly billing.

That does not automatically make BobWork the right choice. If your 20 mailboxes are all Microsoft 365, BobWork is not an option yet. If your team wants a shared pool with outside inboxes, Warmup Inbox may still fit better.

If your mailboxes are Gmail, Google Workspace, Zoho, Yahoo, iCloud, Lark, SES, SendGrid, Mailgun, or standard IMAP+SMTP, the cost difference is worth checking.

Do not let price push you into unsafe sending. For an existing domain, warm for at least 14 days. For a new domain, plan 3–4 weeks. During campaigns, keep warm-up around 10–15/day and real outreach around 30–50/day per mailbox. Add mailboxes instead of forcing one mailbox to carry too much volume.

If you need a day-by-day plan, use the warm-up schedule generator or read how long email warm-up takes.

Who should stay on Warmup Inbox?

Stay on Warmup Inbox if you use Outlook or Microsoft 365. BobWork does not support those mailboxes yet, so switching would break your workflow.

Stay if you want a shared network. Warmup Inbox lists “30,000+ real human inboxes.” BobWork does not publish a size claim; the live count is on the dashboard.

Stay if you want 75 warm-up messages per day on the cheapest paid plan. BobWork reaches 30/day by default, although the cap can be edited per mailbox up to 100.

Stay if you rely on a provider Warmup Inbox lists directly and BobWork does not, such as ProtonMail or Fastmail. BobWork supports any IMAP+SMTP mailbox, but named provider coverage differs.

Stay if your procurement process prefers a paid product with per-inbox billing and a 7-day trial. Some teams need an invoice-backed paid tool rather than a free utility.

Stay if your current deliverability problem is not warm-up. Broken SPF, missing DKIM, no DMARC, high complaint rates, bad lists, or aggressive sending will not be fixed by switching tools. Start with why emails go to spam before changing vendors.

How do you switch safely?

Switch only if your mailboxes are supported (two or more if you want a private pool).

1. Check mailbox support

List every mailbox you want to warm. Mark the provider beside each one.

BobWork supports Gmail and Google Workspace, Zoho Mail, Lark Mail, Yahoo Mail, iCloud Mail, Amazon SES, SendGrid, Mailgun, and any IMAP+SMTP mailbox. Outlook and Microsoft 365 are not supported yet.

For SES, SendGrid, and Mailgun, BobWork uses the platform's SMTP credentials for sending and the receiving inbox over IMAP. You need both sides working.

2. Check authentication

Before you connect, check SPF, DKIM, and DMARC. Warm-up works best when your domain already passes basic authentication.

BobWork checks these records daily after connection. It looks for common DKIM selectors including google, zmail, default, selector1, selector2, k1, s1, mail, dkim, lark, feishu, and zoho.

If your records fail, fix them before increasing any sending volume.

3. Sign in with email code

Go to BobWork Email Warm-up. Sign in with an email code. There is no password and no credit card.

Create your account, then add your mailboxes. One is enough on the shared network; a private pool needs two.

4. Connect each mailbox

For Gmail or Google Workspace, use Google sign-in or IMAP with an app password. If you use Google sign-in, expect Google's unverified-app notice. The requested scope is gmail.modify.

For Zoho, use the Zoho Mail API with a Self Client code, or IMAP on Mail Lite and higher. For Lark, use IMAP and a mail-client password. For Yahoo and iCloud, use IMAP and an app password.

For any IMAP+SMTP mailbox, enter the server, port, username, password, and sender details your provider requires. Check the provider's current limits rather than assuming one standard number.

5. Let the ramp run

BobWork starts each mailbox at 3 emails/day, adds 2 per day, and caps at 30/day by default. Sends happen from 09:00–18:00 in the mailbox's own time zone. Weekends run at 30%.

Do not start aggressive outreach on day one. Use the readiness rule: 14+ days warming, 7-day spam rate at or below 3%, and at least 30 warm-up emails received.

If a mailbox rises above a 5% spam rate, pause it for a few days. Fix authentication, sending content, and volume before restarting.

What should you check now?

Use this checklist before cancelling anything. Avoid gaps in mailbox activity, and do not move unsupported mailboxes.

Keep Warmup Inbox if you need Outlook, a shared 30,000+ inbox network, or 75/day on Basic. Try BobWork if your mailboxes are supported and paying per inbox no longer makes sense. Connect your mailboxes, let the ramp run, and judge readiness by spam rate, days warmed, and received warm-up volume.

What else should you know?

Is BobWork a free alternative to Warmup Inbox?

Yes, if you use Gmail, Google Workspace, Zoho, Lark, Yahoo, iCloud, SES, SendGrid, Mailgun, or IMAP plus SMTP. BobWork is free with no card and supports up to 20 mailboxes per account. It does not support Outlook yet.

Does Warmup Inbox support Outlook?

Yes. Warmup Inbox lists Outlook and Microsoft 365 support on its pricing page. BobWork Email Warm-up does not support Outlook or Microsoft 365 yet because Microsoft requires OAuth.

Which tool sends more per day?

Warmup Inbox Basic lists 75 warm-up messages per day. BobWork starts at 3/day, adds 2/day, and caps at 30/day by default. The cap is editable per mailbox up to 100.

Is a shared network better?

Neither model is always better. A shared network gives you outside mailboxes. A private pool keeps warm-up traffic only between your own mailboxes. Choose based on whether you value network size or tighter privacy and control.

How many mailboxes does BobWork need?

One mailbox is enough on the shared network. BobWork needs at least 2 mailboxes only in private-pool mode, because one mailbox cannot form a private pool by itself.

Can warm-up guarantee inbox placement?

No. Warm-up can create steady engagement between mailboxes, but it cannot guarantee inbox placement. Authentication, complaint rate, list quality, sending volume, and content still matter.

Frequently asked questions