New Microsoft Sender Requirements: Link Roundup

By now, you've probably heard: Microsoft has officially joined the club. Following in the footsteps of Google and Yahoo, Microsoft has announced new requirements for high-volume and bulk email senders targeting their consumer domains (the biggest ones being Outlook.com, Hotmail, MSN, and Live.com).

I first broke the news in April here at Spam Resource, highlighting that this means all four major B2C mailbox providers (Gmail, Yahoo, Apple, and now Microsoft, aka MAGY) are raising the bar on email authentication and best practices.

The Absolute Latest

Hot off the press as of the afternoon of April 29, 2025: Microsoft has updated their guidance to indicate that, starting May 5th, they'll reject non-compliant bulk mail. Previously, their initial plans were to route non-compliant mail to the junk/spam folder.

My Explainers and Guide

If you're looking for help navigating the new rules, I've also put together a practical guide to get you compliant: 2025 Microsoft, Apple, Google, Yahoo (MAGY) Sender Compliance Guide.

You can also catch a couple videos I recorded to help explain everything:

• Microsoft's New Sender Requirements Explained
• MAGY (Microsoft, Apple, Google, Yahoo) Sender Requirements In Detail

For those who want to go right to the source, here's Microsoft's official announcement:
Strengthening the email ecosystem: Outlook's new requirements for high-volume senders

My Valimail colleague Alyssa put together a comprehensive compliance guide, which you can find here. It incorporates the latest updates (i.e. that Microsoft plans to block, not just junk, non-compliant mail).

More Industry Coverage

Plenty of other smart folks in the email world have weighed in as well. Here's a roundup of great articles and blog posts digging into the details:

• Valimail: Microsoft Announces Email Sender Requirements. A solid overview of what's changing and why it matters.
• Mailgun: Microsoft Sender Requirements: What They Are and How to Prepare. Good breakdown of technical and policy updates.
• Moosend: Microsoft's New Requirements for High-Volume Senders. Quick, digestible guide focused on marketing teams.
• The SSL Store: Microsoft Bulk Sender Authentication Requirements Explained. They go deep into DMARC, SPF, and DKIM.
• EasyDMARC: Outlook's New Email Sender Policy Update. Helpful if you need to brush up on authentication protocols.
• Kickbox: Microsoft Outlook Rolls Out New Rules for High-Volume Senders. Includes key timelines and action steps.
• GetResponse: Microsoft Authentication Requirements for Email Senders. Especially useful for marketing platforms and ESPs.
• Braze: 2025 Microsoft Outlook Email Updates: What Marketers Need to Know. Good advice for brand-side email marketers.

What This Means

If you're a bulk sender and you haven't already buttoned up your SPF, DKIM, DMARC, and easy unsub practices, now's the time. Between Google, Yahoo, Apple, and Microsoft, the days of "maybe it's fine if we don't have DMARC" are officially over.

Need help? Again, I recommend starting with my compliance guide — it walks you through everything you need to know to stay out of the spam folder in 2025 and beyond.