Warm up your Outlook or Microsoft 365 inbox.
Land in Focused, not Junk. Warmup Inbox builds your sender reputation across Microsoft's filtering layers — Outlook.com, Microsoft 365, and Exchange Online — automatically, with one-click OAuth setup.
Why warm up your Outlook inbox?
Microsoft's filtering — Defender, Exchange Online Protection, the Focused/Other split — is among the strictest in the industry. Cold outbound from a new Outlook or M365 sender lands in Junk fast. Warmup builds the trust history Microsoft requires.
New Outlook senders go to Junk
Without engagement history, Microsoft Defender treats your sends as suspicious. Cold campaigns get filtered before recipients even see them.
Warmup builds Focused-folder reputation
Real Outlook and M365 inboxes engage with your warmup messages. Microsoft starts placing your campaigns in Focused — where buyers actually look.
What will you love about us?
Simplicity
OAuth via Microsoft. No app passwords, no Exchange admin work. Click connect and you're warming.
No fake inboxes
Real Outlook and Microsoft 365 inboxes in our network. Microsoft's filters see legitimate engagement, not bot traffic.
Fair price
Plans start at $15/inbox/month annually. No unnecessary fees, no feature lock-ins.
Connect Outlook in 30 seconds
OAuth via Microsoft, two clicks, you're warming.
Sign in with Microsoft
One-click OAuth. Grant Warmup Inbox permission to send and receive on your behalf — Microsoft handles authentication.
Activate warmup
One click. Reputation builds across Outlook, M365, Gmail, Yahoo from day one.
Frequently asked questions
Does this work with Microsoft 365 and Office 365?
Yes — Microsoft 365, Office 365, Outlook.com, Hotmail, Live, and Exchange Online all work. The OAuth flow handles authentication for any Microsoft-hosted mailbox.
Will Microsoft Defender flag this as suspicious?
No. The integration uses Microsoft's official OAuth — you grant permission, Microsoft authorizes. There's no app-password workaround or basic-auth bypass that would trigger Defender alerts.
Can I warm up Exchange on-prem accounts?
For on-prem Exchange, we connect via SMTP/IMAP with credentials. Get in touch and we'll walk through the setup — most on-prem deployments work without changes.
How does this affect Focused / Other classification?
Warmup engagement signals tell Microsoft's algorithm that your sender is one users want to read — pushing campaigns into Focused. Most teams see Focused-folder placement lift within 21 days of consistent warmup.
How long until Outlook reputation improves?
Most users see Junk-rate drop and Focused-folder placement improve within 14–21 days. Brand-new M365 tenants take 30–45 days for full warmup maturity.
Land in Focused, not Junk
Warm your Outlook or Microsoft 365 inbox in under a minute. Your campaigns reach the inbox; your team focuses on replies.