Reach personal inboxes
Improve reach across the personal inboxes customers use every day, with placement results for each provider.
A Warmup Inbox alternative for a steadier sending ramp.
Prepare the sender, follow inbox placement and check the email your audience will open. MailSlurp brings the work into one workspace.
Trusted by teams at
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
Reach business inboxes
Check available Microsoft 365 and Google Workspace samples before increasing business email volume.
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
Grow without sudden spikes
Increase sending volume in steady steps that build trust instead of triggering the reputation damage caused by abrupt spikes.
Keep the sender healthy
Keep authentication, domain health, and blocklist signals in view while the sender builds a stronger delivery record.
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
Know exactly where mail lands
Measure inbox, Promotions, spam, and not-received outcomes instead of treating provider acceptance as the finish line.
Catch placement changes early
See when inbox reach changes during the ramp and adjust before important customer campaigns are affected.
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
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 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.
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.
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.
