# A Warmup Inbox alternative for a steadier sending ramp.

Warm your sender in MailSlurp and follow provider placement results. Review progress, investigate delivery changes and test campaigns before sending.

Prepare the sender, follow inbox placement and check the email your audience will open. MailSlurp brings the work into one workspace.

[See warmup plans](https://app.mailslurp.com/pricing/?focus=deliverability\&onboardingRequest=warmup) [Explore email warmup](https://www.mailslurp.com/alternatives/warmupinbox/#customer-reach)

![Illustration of a campaign arriving in the inbox with Gmail, Outlook and Yahoo](https://www.mailslurp.com/_astro/campaign-inbox-result-v3.DaNBGMEE_Z1auuHo.png)

Trusted by teams at

- ![Broadcom](https://www.mailslurp.com/assets/companies/broadcom.svg)
- ![Scraper](https://www.mailslurp.com/assets/companies/scraper.svg)
- ![Trivago](https://www.mailslurp.com/assets/companies/trivago.svg)
- ![Avast](https://www.mailslurp.com/assets/companies/avast.svg)
- ![Wolt](https://assets-cdn.mailslurp.com/image-variants/340/assets/companies/wolt.png?v=5ce9129fcee5e41e3d25b05cebde2303276bc5c7)
- ![Panasonic](https://www.mailslurp.com/assets/companies/panasonic.svg)

## Reach customers across every major inbox.

Build sending history gradually and check placement across available Gmail, Outlook, Yahoo, and other provider samples as your schedule progresses.

Track inbox, Promotions, spam, and not-received results throughout the ramp to make informed decisions before increasing campaign volume.

[Improve inbox placement](https://app.mailslurp.com/sign-up/?onboardingRequest=warmup\&returnTo=%2Femail-warmup%2Fcreate%2F%3FonboardingRequest%3Dwarmup)

![A campaign email reaching customer inboxes](https://www.mailslurp.com/_astro/customer-reach-v2.c0tBmZDl_1Flxno.png)

![Yahoo, Gmail, Outlook, Proton Mail, and iCloud provider cards](https://www.mailslurp.com/_astro/personal-provider-cluster-five.DkVEEFep_Z2teRKi.png)

### Reach personal inboxes

Improve reach across the personal inboxes customers use every day, with placement results for each provider.

![Microsoft 365 and Google Workspace provider cards](https://www.mailslurp.com/_astro/professional-provider-cluster-microsoft.rFkErQJ3_Z1j363L.png)

### Reach business inboxes

Check available Microsoft 365 and Google Workspace samples before increasing business email volume.

![Spam score improving over repeated delivery checks](https://www.mailslurp.com/_astro/spam-score-history.dYSHYKpX_Z11rrAD.png)

### Move further from spam

Compare inbox and spam results over time to see whether your sender is ready for more volume.

## Build the reputation behind every campaign.

New and recovering senders need a record of consistent, successful delivery. MailSlurp creates that history before launches, promotions, lifecycle messages, and customer notifications depend on it.

Volume grows in measured steps while receipt, placement, and sender-health observations stay visible.

[Build sender reputation](https://app.mailslurp.com/sign-up/?onboardingRequest=warmup\&returnTo=%2Femail-warmup%2Fcreate%2F%3FonboardingRequest%3Dwarmup)

![Campaign email moving from Promotions to the Primary inbox on iPhone](https://www.mailslurp.com/_astro/promotions-to-primary-warmup-v3.BVomxUft_2r1I5Y.png)

![Sending volume increasing in safe measured steps](https://www.mailslurp.com/_astro/safe-volume-growth-v2.BvgHQvmT_ZWEVQR.png)

### Grow without sudden spikes

Increase sending volume in steady steps that build trust instead of triggering the reputation damage caused by abrupt spikes.

![SPF, DKIM, DMARC, and blocklist health checks](https://www.mailslurp.com/_astro/domain-health-checks.Db5d72SP_ZUKrRA.png)

### Keep the sender healthy

Keep authentication, domain health, and blocklist signals in view while the sender builds a stronger delivery record.

![Sender recovery trend rising back toward the inbox](https://www.mailslurp.com/_astro/sender-recovery-v2.myr17c-I_Z1l6vTV.png)

### Recover lost trust

Use a measured recovery schedule to observe an existing sender and decide when to increase volume.

## Protect deliverability while volume grows.

MailSlurp uses controlled inbox receipts, delivery failures, domain health, Gmail Postmaster data, and placement tests to choose the next target. Strong signals keep the ramp moving; weaker signals slow it before customer reach drops.

Use each step to assess delivery before increasing volume. Placement also depends on your authentication, content, and recipient engagement.

[Start adaptive warmup](https://app.mailslurp.com/sign-up/?onboardingRequest=warmup\&returnTo=%2Femail-warmup%2Fcreate%2F%3FonboardingRequest%3Dwarmup)

![Adaptive sending volume increasing, holding, and resuming](https://www.mailslurp.com/_astro/adaptive-volume-plan-v3.C_ASRzSd_ZjmkxG.png)

![Email placement across inbox, Promotions, and spam](https://www.mailslurp.com/_astro/hero-compact.CKgc5_3t_bwXuF.png)

### Know exactly where mail lands

Measure inbox, Promotions, spam, and not-received outcomes instead of treating provider acceptance as the finish line.

![Inbox placement history revealing a delivery change](https://www.mailslurp.com/_astro/monitoring.BxQh14Y9_12b4SI.png)

### Catch placement changes early

See when inbox reach changes during the ramp and adjust before important customer campaigns are affected.

![Slack and Microsoft Teams delivery notifications](https://www.mailslurp.com/_astro/slack-teams-notifications.BV9iqo5I_2jWd39.png)

### Keep the team ahead

Bring placement changes into Slack or Microsoft Teams so the people protecting deliverability can act quickly.

## Warm up every sender you already use.

Connect your provider through a supported native integration or authenticated SMTP, then warm up the mailbox, domain, and identity used for your customer email.

Use SendGrid, Resend, Amazon SES, Mailgun, Postmark, Gmail, Microsoft 365, Yahoo, Zoho, Fastmail, Brevo, Mailjet, and more.

[Connect your provider](https://www.mailslurp.com/docs/email-warmup/#connect-a-sender)

![SendGrid, Resend, Amazon SES, and Mailgun provider cards](https://www.mailslurp.com/_astro/sender-provider-cluster-v2.ZprTTed5_Z28UEst.png)

## How to start warming your sender

### Connect and verify the sender

Choose a supported provider or authenticated SMTP connection. Verify the From address and complete the test delivery. The [provider guides](https://www.mailslurp.com/docs/email-warmup/#provider-setup-guides) explain the connection details.

### Choose a gradual schedule

Set a new-sender or recovery goal, daily target, time zone and sending window. Include your regular campaigns in the total volume and avoid overlapping warmup programs.

### Follow results before increasing volume

Check accepted sends, observed receipts and completed provider placement results. Investigate repeated failures before adding volume, then test the finished campaign through its normal ESP. Read the [warmup results guide](https://www.mailslurp.com/guides/email-warmup-inbox-placement/).

## Carry your sending context into the switch.

### Plan around your real sending path

Keep the From address, provider, recent volume and sending hours close at hand. Connect the supported sender to MailSlurp and choose a gradual schedule that accounts for both warmup activity and your regular campaigns.

### Read sends, receipts and placement separately

Use accepted sends, observed receipts and completed provider placement checks for the different questions they answer. When the campaign is ready, send it through its real ESP to a placement test and a render inbox. Review the folders, design, links and images before launch.

## Questions before you switch?

Does an accepted warmup send mean the email reached the inbox?

An accepted send confirms that the sending service took the message. A completed receipt or placement check provides the next evidence about what happened at the receiving mailbox. In MailSlurp, review those observations separately and compare equivalent provider samples over time. Test your actual campaign through its normal ESP before scheduling a larger send. [Understand accepted sends and placement checkpoints.](https://www.mailslurp.com/guides/email-warmup-inbox-placement/)

Can I keep my sending provider?

Yes. Connect a supported sender directly or through authenticated SMTP, verify the From address and complete the test delivery. Use your normal ESP separately for a representative campaign placement test.

Which plans include warmup?

MailSlurp warmup is available on Pro and Growth. Sending usage is billed beyond included credits. Compare the current sender capacity, credits and placement coverage before choosing a plan.

## Build sending history. Check the next campaign.

Choose your sender capacity, placement coverage and campaign checks.

[See warmup plans](https://app.mailslurp.com/pricing/?focus=deliverability\&onboardingRequest=warmup)

![Email previews across mobile and desktop clients](https://www.mailslurp.com/_astro/device-client-coverage-v2.DoropbIo_FhjiF.png)