Email Deliverability in 2025: New Rules, Higher Standards, and What B2B Marketers Should Do

Email deliverability – the ability to get marketing emails into recipients’ inboxes – has always been a concern for marketers. But recent moves by the major email providers are raising the bar on what it takes to reach the inbox. 

In May 2025, Microsoft rolled out significant deliverability changes, including stricter authentication requirements and new recommended practices for senders. This follows on the heels of Google and Yahoo updating their own sender guidelines in late 2023 and 2024. 

The message from the big email service providers is clear. To ensure emails land in front of clients and prospects, marketers must up their game in authentication, list management, and sender practices.

Microsoft’s May 2025 Deliverability Changes

The headline from Microsoft’s announcement is that senders who exceed 5,000 emails per day to Microsoft’s consumer email services must implement DMARC email authentication, in addition to the long-standing SPF and DKIM standards.

In other words, high-volume domains must publish a DMARC policy in their DNS records and have their messages pass DMARC checks—otherwise, Outlook’s filters will treat them as suspect and reject them.

These rules apply only to Microsoft’s consumer email services and do not currently affect Microsoft 365 enterprise mailboxes due to the more complex email flows of enterprise environments. ​​However, best practice recommends that all organisations pay attention, as similar requirements may be introduced for business mailboxes in the future.

Beyond the DMARC mandate, Microsoft also announced four email hygiene practices they strongly recommend and warned it may filter or block senders who don’t follow them. These aren’t hard requirements yet, but they signal where things are heading. 

Reply-able Sender Addresses 

Microsoft wants the “From” and “Reply-To” addresses on your emails to be valid, aligned with your sending domain, and able to receive email. In other words, they don’t want you sending from noreply@yourdomain.com or similar addresses. 

For many brands, using a valid domain in the From line is standard, but ensuring someone monitors the replies might be a new step. 

List Hygiene & Bounce Management 

Microsoft advises senders to regularly remove invalid or non-responsive addresses from their lists. Practically, this means actually doing what we all know we should be doing: keeping your email list clean. 

A “hygienic” list wastes less bandwidth and is less likely to generate spam complaints or be targeted by spammers. If you keep emailing outdated addresses, you’ll see high bounce rates and maybe even spam reports (“I don’t recall signing up for this”). By scrubbing such contacts regularly, you avoid needless bounces and complaints, improving deliverability.

Easy Unsubscribe Links

Microsoft’s guidance here is straightforward: if recipients don’t want your emails, let them opt out with one click. Notably, Microsoft stopped short of requiring the email header List-Unsubscribe, which Gmail and Yahoo do mandate for high-volume senders. However, savvy marketers should implement it anyway because it allows email clients to show an official “Unsubscribe” button or link next to your email.

Transparent Mailing Practices 

So far, so simple. And Microsoft’s final recommendation is also not exactly rocket science either. They ask you to be truthful and clear in your email content and obtain proper consent. 

In practice, this covers basics like using accurate subject lines and avoiding clickbait or deceptive headers, and clearly identifying yourself as the sender. It also means only emailing people who have given consent to hear from you.

Microsoft are essentially saying: If you want good deliverability, behave ethically and as if stricter laws like Europe’s GDPR apply in your jurisdiction. 

Microsoft has signalled that while only DMARC is an outright requirement today, these four best practices are likely precursors to future requirements. What’s “recommended” now could become “required” in the near future. For B2B marketers, the takeaway is to treat these not as optional tips but as must-do actions to keep your email programmes healthy.

Beyond Compliance: Improving Deliverability and Building Trust

These aren’t arbitrary hoops to jump through – they align with practices that will improve your users’ experience and keep your audience more engaged. 

We thought we’d take this opportunity to review a range of steps you can take in this spirit to improve your deliverability right now. These steps blend the explicit requirements from mailbox providers with broader best practices for healthy email marketing.

Strengthen Your Email Authentication (SPF, DKIM, DMARC)

Email authentication is the foundation of modern deliverability. If you’ve been treating it as an IT formality, it’s time to give it executive attention. 

All three major providers – Microsoft, Google, Yahoo – now expect senders to have SPF and DKIM in place, and to publish a DMARC policy. Here’s what to do:

1 - Ensure SPF and DKIM are correctly implemented for all sending domains

SPF (Sender Policy Framework) is a DNS record that lists which servers can send email for your domain. DKIM (DomainKeys Identified Mail) is a cryptographic signature added to each email to verify it wasn’t altered and truly comes from your domain. 

Work with your IT team or ESP to double-check that your SPF record is up to date (including all services you use to send email) and that DKIM signing is turned on for your email streams. Providers now require both SPF and DKIM for senders at scale, not just one. If you’re missing one, fix that immediately.

2 - Publish a DMARC policy (even if it’s just monitoring mode for now)

DMARC (Domain-based Message Authentication, Reporting and Conformance) ties together SPF and DKIM by requiring 'alignment'. It tells receivers how to handle emails that fail authentication and provides visibility through aggregate reports.

Alignment means the domain in your From header must match either your SPF domain or DKIM domain. Common implementation failures might include:

• You use a marketing platform that sends from their servers, but your From address says "marketing@acmeconsulting.com". If their IP isn't in your SPF record and they're not DKIM-signing with your domain, DMARC fails.

• Your website is acmeconsulting.com but emails come from a subdomain such as mail.acmeconsulting.com. Unless your DKIM and SPF explicitly cover subdomains, alignment can break.

• Your newsletter comes from one platform, your sales emails from another, and your transactional emails from a third. Each needs proper authentication under your domain.

Work with your email service provider, asking specifically about "DMARC alignment" – don't assume it's configured correctly by default.

At minimum, set up a DMARC record with p=none (monitoring) for your domain. This alone will satisfy the current requirement and start generating DMARC reports. Those reports are gold: they show you which IPs and services are sending email claiming to be from your domain. 

Often, brands discover forgotten systems or unauthorised senders this way – things that could be cleaned up or properly authenticated. Simply having a DMARC record signals to mailbox providers that you’re taking responsibility for your domain’s mail.

3 - Move toward a stricter DMARC policy when ready

Microsoft’s 2025 stance hints that they will eventually move to stricter policies, and Gmail/Yahoo’s long-term aim is to fight spoofing by having everyone move to enforcement. So don’t stop at p=none forever. 

The ultimate goal should be to enforce DMARC, meaning phishing or otherwise unauthenticated emails purporting to be you will be filtered or blocked by receivers. 

Once you’re confident all legitimate email senders for your domain are identified and authenticated, consider shifting to p=quarantine (which will put failing messages into spam) and then to p=reject (which outright drops failing messages). 

This progression typically takes several months rather than weeks—you need sufficient time in monitoring mode to identify all your legitimate sending sources before moving to enforcement. Organisations with complex email infrastructures—multiple sending services, subdomains, or third-party tools—often need longer to ensure everything is properly authenticated.

Many large companies and savvy senders have already done this to protect their brand – for instance using p=reject to prevent any phishing attempts using their domain. This can also give a minor deliverability boost. Mailbox providers know that a domain with a strict DMARC is highly likely to be a reputable sender, since any forgeries will get bounced. It’s a long-term project, but one worth pursuing for peace of mind and enhanced trust.

4 - Monitor your authentication results and fix issues promptly

Set up a routine to review DMARC aggregate reports. They will tell you if, for example, some emails are failing DKIM because of a broken signature, or if an IP not in your SPF tried to send mail for you. 

If you see DMARC failures for legitimate mail, track down the cause – perhaps a new third-party tool wasn’t included in SPF, or DKIM wasn’t configured on a subdomain. Additionally, you can use tools like Gmail’s Postmaster Tools and Microsoft’s SNDS (Smart Network Data Services) to check if your domain is passing authentication consistently and what your reputation looks like.

In summary, robust authentication is no longer optional. It’s a requirement, but it is also an opportunity. It protects you from spoofers, helps ensure your emails aren’t mistaken for fakes, and is the price of entry to recipients’ inboxes in 2025. Make sure your SPF, DKIM, and DMARC are rock solid – this is one deliverability investment that pays dividends in security and reputation.

Embrace Easy Unsubscribing and Subscription Management

Nobody likes losing subscribers, but making it easy for people to opt out is actually a hallmark of a healthy email programme. The latest moves by email providers essentially force marketers to adopt a subscriber-friendly philosophy: let people leave if they want to. 

Here’s how to align with that and even benefit from it:

1 - Include a clear unsubscribe link in every email

Every marketing email you send should include an easy-to-find, working unsubscribe link. If people can’t easily unsubscribe, they’re more likely to hit the “Report Spam” button, which damages your sender reputation. Far better to let them go gracefully.

You probably do this already, but it is worth checking your email templates. Despite this being a legal requirement for forever (CAN-SPAM in the US and similar laws elsewhere), you wouldn’t believe the misguided workarounds we’ve seen people use to try to keep people on their list against their will.

The link should be prominent enough that a disinterested recipient can find it in a few seconds. A good placement is usually in the footer, but not buried in a paragraph of legalese or in such small print that you need a magnifying glass to find it.

Make sure that when someone clicks it, the process is painless. Ideally the user should receive confirmation after just one-click. At most, you can present them with a short preferences form. Say, for example, you want to give them the option to hear from you less frequently.

Finally, test your unsubscribe link periodically! It’s surprising how often changes in an email template or website cause the unsubscribe process to break. A broken unsubscribe is one of the fastest ways to generate spam complaints and anger mailbox providers. Microsoft explicitly defines a “functional” unsubscribe link as one that works reliably when clicked.

2 - Implement the List-Unsubscribe header with one-click functionality

This is a technical step, but many ESPs allow you to turn it on with a setting. The List-Unsubscribe header adds an invisible piece of information to your emails that email clients can use to streamline opt-outs. 

When configured, email providers show an “Unsubscribe” link next to the sender’s address at the top of the email, which users love because it saves them hunting for your link. Implementing this not only keeps you compliant, it also likely helps your deliverability. Recipients who use the native unsubscribe are effectively telling the mailbox provider “this wasn’t spam, I just don’t want it anymore,” which is a much cleaner signal than a spam complaint. So overall, it’s a best practice to adopt universally.

3 - Honour unsubscribe requests quickly and fully

This might seem obvious, but ensure that when someone opts out, they are truly and promptly removed from all relevant mailing lists. Yahoo’s policy states it expects senders to honour opt-out requests within 2 days, which is a good benchmark. However, faster is better and instantaneously is best. 

If you manage multiple mailing streams (newsletters, event invites, product updates), consider providing a preference centre where subscribers can choose which communications they want, rather than all-or-nothing. However, do not use that as a way to obscure the one-click global unsubscribe. The one-click should always be an option; a preference page is a nice extra, but not a substitute. Once someone has said they want out, verify that you stop emailing them – nothing kills trust like an “unsubscribed” person receiving another email next week.

Keep Your Data Clean: Practice Good List Hygiene and Data Management

Microsoft’s recommendations and Yahoo/Gmail’s requirements both emphasise maintaining a clean list. This is arguably the most “unsexy” part of email marketing, but it’s absolutely vital. A clean email list not only helps with deliverability; it also means you’re not wasting effort on dead ends. Key actions include:

1 - Remove invalid addresses and hard bounces aggressively

Email providers interpret high bounce rates as poor list management, which is often associated with spammers or negligent senders. Keeping your bounce rate low is thus part of staying in the “trusted sender” club.

If an email address is bouncing as “address not found” (a hard bounce), take it off your list immediately. Most email platforms do this for you by default – they’ll put that address on a suppression list. Make sure that’s happening. Under no circumstance should you keep retrying a hard-bounced address or, worse, purchase some list of “updated” emails for those contacts. 

Bounces hurt your sender reputation if they happen in large numbers. They’re also a sign that your data might be stale. If you have a bunch of bounces from a particular source (say, a specific event list from 3 years ago), it’s a clue that the data source needs evaluation. 

2 - Monitor soft bounces and spam trap hits

Not all bounces are permanent – some are “soft” (e.g., mailbox full, or temporary server issue). If the same addresses keep soft bouncing for months, consider removing them too, as they may effectively be dead, abandoned, or “grey mail” accounts. 

Additionally, watch out for any signs that you might be hitting spam traps. These are email addresses set up by inbox providers or security entities to catch senders who are not practicing good hygiene. They often appear on lists that were purchased or scraped, or if you’re mailing to very old addresses. If you suddenly see an unusual bounce or block that mentions things like “spam trap” or “listed”, you may need to audit your list acquisition sources.

3 - Don’t buy lists and be cautious about third party data

This should go without saying in 2025, but it’s worth repeating. Purchased lists are deliverability poison. Not only are the recipients truly “cold” (and likely to mark you as spam since they don’t expect your email), these lists often contain spam traps and outdated addresses galore. 

If your firm uses third-party lead sources (like event attendee lists, association member lists, etc.), treat them with care. Ideally, you should send an initial email that invites them to opt-in, rather than dumping them straight into your main marketing stream. 

We all understand the pressure to grow the database, but quality trumps quantity here. A smaller list of genuinely interested contacts will outperform a huge list of strangers every time, especially now that mailbox providers are watching engagement metrics like hawks.

4 - Use confirmed (double) opt-in for new subscribers where feasible

While double opt-in–where a new subscriber has to click a confirmation email to be added–isn’t strictly required by law or providers, it’s a gold standard for list quality. It ensures the address is valid (they had to receive the confirmation email) and that the person truly wants to be subscribed (they clicked to confirm). It eliminates typos (no more Bob at gmial.com by mistake) and prevents people from maliciously signing others up without consent.

Yes, you may lose a few sign-ups who don’t bother to confirm, but those are likely the folks who would never engage anyway. The result is a cleaner, more engaged list that’s less likely to incur complaints or bounces. If double opt-in isn’t suitable (say, for gated content downloads where the user expects the content immediately upon sign-up), at least consider sending a welcome email that sets expectations and allows them to verify their address or preferences.

5 - Proactively remove chronic non-responders or disinterested recipients

It might feel counterintuitive for marketers to remove people voluntarily, but don’t keep sending to people who never show signs of life. If a segment of your list hasn’t engaged in a year or more, you should consider removing them, even if they never bothered to unsubscribe. 

Why? Firstly, because an uninterested subscriber is one step away from being an annoyed subscriber, and an annoyed subscriber might hit “Report Spam” the next time you show up in their inbox.

Secondly, ISPs have systems that penalise senders with a high proportion of “ghost” recipients. For example, if 90% of people ignore your emails, Gmail might downgrade you compared to a sender that gets 50% opens. Trimming the dead weight improves your metrics and deliverability.

Some organisations set a policy like “if no opens or clicks in 12 months, we stop emailing them.” Define what makes sense for your sales cycle – in some B2B contexts a contact might only engage when they have a need, so you might set a longer horizon.

You can periodically send a re-engagement email (“You haven’t opened our emails in a while. Do you still want to hear from us? Click here to stay subscribed.”) to weed out those who don’t respond. Those who don’t click can be safely assumed to be no longer interested and dropped.

This kind of list hygiene keeps your list full of genuinely interested people, and sends a strong signal to Gmail/Yahoo/Outlook that your emails are welcomed by recipients. You’ll enjoy higher open rates, lower complaint rates, a better reputation with mailbox providers, and a healthier relationship with your audience.

In practice, good list hygiene requires a mix of technology and policy. If you need buy-in, show leadership that a leaner, well-maintained list will lead to better campaign performance and less risk of being blocklisted or spam-foldered. This is very much a case of quality over quantity.

Use a Recognisable, Responsive Sender Identity

Microsoft’s push for “compliant sender addresses” highlights something every marketer should rethink: the email address and sender name you use to send campaigns. It’s part branding, part functionality:

1 - Ditch the “no-reply” and generic addresses

If any of your emails still come from an address like no-reply@company.com or newsletter@company.com that isn’t monitored, make a plan to change that. Not only does “no-reply” sound unfriendly and imply “we don’t want to hear back from you”, but it also prevents valuable interactions. 

B2B subscribers do reply to marketing emails more often than you might think – sometimes to ask for more information, to point out an issue (like a broken link), or even to express interest in a service. 

Adopting a reply-friendly policy fixes that disconnect. By ensuring those replies go to a live, monitored mailbox, potential leads or feedback won’t be missed.

2 - Use a consistent, recognisable sender name

The sender name is what users see in their inbox list, often together with or instead of the email address. It establishes trust: people tend to engage with senders they know. If your sender name and address establish that it’s an official communication from your firm, recipients are more likely to open it (and less likely to mark it as spam).

• It should clearly identify your company or brand. For example, “Acme Consulting Insights” is better than just “Acme Consulting” or a person’s name they won’t recognise. 

• It should be consistent. If one week your newsletter comes from “Acme Consulting Marketing” and the next week from “John at Acme Consulting”, users might not realise it’s the same sender. 

• Avoid gimmicky or misleading sender names (don’t put “Re:” or “Fwd:” in the name, obviously, and don’t pretend to be an individual unless that person truly is who the email is from).

3 - Set up a system to handle replies

Once you invite replies by using a real email address, be prepared to handle them. Depending on your volume, this might mean routing replies to a shared inbox or using an email management tool. 

Some marketing platforms offer automated filtering for replies – for instance, separating out auto-replies (out-of-office messages, etc.) from genuine human responses. Make use of those features so you can focus on real replies. 

For the human responses, have a workflow. If someone asks a question, do you have a set of standard responses and resources to hand and a team member ready to respond? If they request a sales contact, how do you route that to sales? 

Treat replies as opportunities to engage one-on-one. They can provide feedback (“I had trouble accessing your webinar”), leads (“We might be interested in your services; can someone call me?”), or at least insights into how your emails are being received. 

On the flip side, if you never monitor replies, you might also miss anger or frustration signals – e.g., someone replying “unsubscribe me” or “I keep marking you as spam, why won’t you stop?” If you catch those, you can manually remove them and avoid a spam complaint. It’s all part of being a responsible sender.

In short, your sender identity should invite engagement, not discourage it. It humanises your email programme and aligns with mailbox providers’ expectations that senders will be accountable.

Set the right expectations and Send Relevant Content

Even with all the technical fixes, we must remember that email deliverability at its core comes down to how recipients react to your emails. Content and sending practices that foster trust and engagement will always pay off. The providers’ guidelines about transparency and only sending wanted emails tie directly to content strategy:

1 - Use truthful, clear subject lines

Subject lines like “Re: Our meeting yesterday” when you had no meeting, or overly sensational claims, might boost opens short-term but will backfire. You’ve probably been on the receiving end and know how tiresome these games can be. Not only do laws like CAN-SPAM prohibit deceptive headers, but if a recipient feels duped, the next click might be the spam button.

Never trick someone into opening an email. If your content is genuinely valuable, you don’t need gimmicks. Just set clear expectations and communicate the value of your offer in the subject line.

2 - Align the email content with what the recipient signed up for

If someone subscribed to your weekly industry insights, that’s what they should get – not surprise product pitches or unrelated content. When subscribers get exactly what they anticipated (and ideally, a bit more value than they hoped), they are far less likely to consider your mail unwanted.

One common mistake is the “scope creep” of mailing lists: a contact downloads one whitepaper and suddenly they’re on three different mailing lists receiving everything from event invites to product announcements. Guard against this. 

Segment your lists and tailor content to the interest the person expressed. Also, honour any frequency you advertised. If you said “monthly newsletter,” don’t start sending weekly because you have more content. If you want to increase frequency, you can always send an email inviting your subscribers to opt-in to a new tier. 

3 - Ensure the body of the email clearly identifies your organisation and purpose

A reader should never have to wonder “Who is this from and why am I getting it?” Clarity here reduces the chance of confusion-driven spam reports. It also projects professionalism – which is key for B2B brands. 

Make sure your company name and logo is visible, include a footer with your contact information (a legal requirement in many jurisdictions), and a perhaps concise description if needed (“You’re receiving this email because you subscribed to X…”). 

The tone and style of your content should match what your brand stands for. If you’re a consulting firm known for thought leadership, keep the tone authoritative and helpful, not salesy hype. Consistency in voice builds familiarity over time.

4 - Avoid spammy keywords and formatting – but don’t overthink it

Modern spam filters are far more sophisticated than looking for words like “free” or “guarantee”. It’s more about context and reputation than specific phrases. 

Still, extremely salesy language or too many exclamation points, ALL CAPS, etc., can trigger content filters. At the very least, they will come across as unprofessional to readers. If your content is valuable and relevant, you shouldn’t need to resort to shouting in text. Also be mindful of your text-to-image ratio. All-image emails or emails with very little substantive text can appear suspicious to filters unless the sender reputation is stellar.

5 - Provide value in every send

This is more of a marketing principle, but it’s worth stating: each email should have a clear value to the recipient – information, insight, an offer they actually might want, etc. 

The best way to keep complaints down and engagement up is to consistently send emails that people want to receive. If you find yourself sending emails just to “check the box” on a weekly schedule without strong content, consider slowing down until you have something truly useful to say. 

Quality matters more than quantity, especially in B2B. It’s better to have slightly fewer emails that are well received, than a high volume that wears out your welcome. Remember, every time someone ignores your email, that’s a tiny hit to your sender reputation. Gmail, for example, considers read rates and delete-without-open rates as part of their engagement metrics. So, making each email count is not just good for conversions, it’s good for deliverability too.

In essence, think of the new rules as nudging us toward the Golden Rule of email: send unto others what you’d like to receive in your own inbox. By being honest in subject lines, respectful of consent, and consistently relevant, you build a loyal audience. Those positive recipient behaviours (opens, clicks, even the occasional reply or forward) feed back into better deliverability, creating a virtuous cycle.

Monitor Deliverability and Adapt Quickly

Don’t treat deliverability as a set-and-forget checklist. It’s an ongoing discipline. The landscape can change and even with all best practices in place issues can arise. Smart marketers will:

1 - Keep an eye on key metrics and thresholds

Regularly review your campaign performance for signs of trouble. If your open rates suddenly drop for Outlook addresses, investigate – it could be that your domain fell out of Microsoft’s good graces and things are landing in Junk. If you see a spike in bounces or a particular error code in bounce messages, take action immediately. 

Use Gmail Postmaster Tools to check your spam complaint rate – if it’s edging toward the danger zone of 0.3%, you have a warning sign to improve content or prune your list. Also, watch the Gmail “reputation” indicators (they rank your domain and IP as High, Medium, Low, or Bad for factors like spam complaints, domain reputation, etc.). Similarly, Yahoo’s postmaster site, Microsoft’s SNDS and the Office 365-delivered messages reports, or third-party services can give insights on whether you’re being filtered.

2 - Set up alerts or reports for authentication failures

As part of your DMARC reporting, you might configure it to send to an analytics tool or a dedicated inbox that you review. If one day you see that 20% of your emails failed DKIM, it could mean a misconfigured DNS or a certificate expiry that you need to fix. If you switch email service providers or add a new sending IP, monitor closely to make sure the new setup is authenticated properly. 

Additionally, you should “warm up” a new IP/domain. This means gradually increasing volume to build a good reputation.

3 - Engage with feedback loops

Many ISPs offer feedback loop services where they inform you of spam complaints originating from their users. Sign up for these through their postmaster sites if you haven’t already. When you get a complaint notification, ensure that address is suppressed from future mailings – they clearly don’t want your mail. 

While Gmail doesn’t provide individual FBL reports, their aggregate spam rate in Postmaster Tools is your guide. Microsoft has a proprietary system. Regardless, act on any complaint data you can get.

4 - Stay informed about industry changes

The email world evolves constantly. Today it’s DMARC enforcement; tomorrow it could be something like BIMI (Brand Indicators for Message Identification) becoming a factor, or perhaps tighter rules around content. For instance, Apple’s Mail app (popular on iPhones even among business users) has introduced features like Mail Privacy Protection, which hides open tracking – not directly a deliverability issue, but it affects how we measure engagement. 

Knowing these trends helps you adapt. To keep up, consider subscribing to email industry blogs, attending webinars, and following what the major providers’ postmaster teams publish. Google’s and Microsoft’s official documentation updates are also worth checking every so often.

5 - Have a crisis plan for deliverability issues

Despite best efforts, you might encounter a serious problem such as your domain getting blacklisted on a major spam list, or Outlook suddenly starts junking all your mail. 

When such things occur, you need to troubleshoot quickly. Identify internally who will take charge. Use tools to diagnose the issue so if you need to reach out to the ISP/postmaster you can do so with evidence of the problem and steps you’re taking. Also, be ready to pause or slow down campaigns if needed while you fix an issue. Blasting ahead when your emails are being flagged can dig a deeper hole. It’s better to resolve the root cause, then resume normal sending.

6 - Coordinate across departments

In B2B companies, marketing might not be the only one sending bulk emails. Sales teams might use their own tools, customer success might send out service updates, IT might send notifications. All these contribute to the overall volume and reputation of your domain. 

Make sure everyone is aware of the new requirements. It’s a great time to put in place a governance policy for email. Often, marketing will take ownership of the domain’s email reputation since you have the most to lose if it goes south, so reaching out to other teams to ensure they aren’t accidentally jeopardising deliverability is important. Don’t let internal silos wreck your hard-earned sender reputation.

By maintaining vigilance and a proactive stance, you can catch issues early and adapt to new rules gradually, rather than in a panic after the fact. Remember that deliverability is not a static thing – it’s a relationship between you, recipients, and mailbox providers that needs nurturing.

Turning Email into an Opportunity for Trust

It’s worth stepping back from the nitty-gritty to appreciate the broader philosophy behind these changes. At first glance, Google, Yahoo, and Microsoft are imposing more rules on us marketers – more hoops to jump through to get our messages delivered. But another way to see it is that they’re nudging everyone to send better emails. And “better” is ultimately in the eye of the recipient.

Rather than viewing compliance as a chore, marketers can use this moment to double down on customer experience via email. Every email is a touchpoint that can either reinforce your credibility or detract from it. By following best practices, you’re inherently making those touchpoints more respectful and value-driven.

Requiring authentication helps protect your brand from phishing and abuse. It ensures that when a client sees your name in their inbox, they can trust it’s really you. That’s a win for brand trust. No senior executive wants to be fooled by a spoofed email from their law firm or consultancy – DMARC makes that far less likely.

Mandating easy unsubscribe and low spam rates forces us to focus on an audience that cares. That, in turn, should improve how well our emails perform. It’s an opportunity to shed dead weight and communicate more personally with those who find our content relevant. Measuring your success by the size of your list is short-sighted. Engagement quality is the new metric that matters. Marketers who embrace that will likely see better ROI from email, with fewer emails sent. It’s like pruning a garden so the healthiest plants can flourish.

Emphasising reply-able addresses and genuine human communication can open new dialogues with clients and prospects. B2B marketing is often about building relationships over long cycles. Encouraging replies and then responding to them can turn a broadcast channel into a conversation channel. It might require some workflow adjustments, but it can uncover leads and insights that no click-through report could ever show you. In a sense, it brings email marketing closer to personal selling, which is a positive shift for many professional services contexts.

Being transparent and permission-based in who you email and what you send builds goodwill. Recipients may not consciously applaud you for sticking to opt-in lists or writing honest subject lines, but subconsciously it affects how they perceive your brand’s communications. Over time, a subscriber who consistently finds your emails useful and unobtrusive will associate your brand with reliability and integrity. On the flip side, if they ever feel tricked or trapped, that erodes trust rapidly. Trust is hard to quantify, but in B2B especially, it’s a currency of its own.

Lastly, let’s address mindset: It might be tempting to treat deliverability as a technical issue to hand off to IT or vendors. But as we’ve discussed, it’s entwined with strategy and content. Senior marketers should champion deliverability as part of the overall marketing strategy. It’s akin to how good SEO is a result of good web content and user experience – good deliverability is the result of good email practices and subscriber experience. It’s not “compliance vs. creativity” or “IT vs. marketing”; it’s a collaborative effort to make sure our communications actually reach and resonate with the intended audience.

Adapting for the Long Run

The email sender requirements in 2025 are telling us something simple that we should already know: deliverability is earned, not given. Microsoft’s new rules, following Google’s and Yahoo’s, reinforce that senders must prove themselves trustworthy and competent custodians of the inbox.

By implementing strong authentication, maintaining a scrupulously clean mailing list, making it easy for recipients to control what they receive, and delivering content that respects the reader’s time and interests, you’ll not only meet these new standards – you’ll likely exceed them. In doing so, your emails stand a far better chance of reaching the inbox and engaging the right people. 

The recommendations in this article serve as a comprehensive checklist. If you haven’t audited your email programme recently, now is the time: check your DNS records and policies, review how subscribers join and leave your lists, and evaluate your email content and sending practices through a fresh lens of “would I find this valuable if I were the client?”

In summary, take Microsoft’s May 2025 update – and the similar moves by Google and Yahoo – as a prompt to elevate your email programme. Clean up what needs cleaning, tighten what needs tightening, and continue to craft communications that respect and engage your audience. Do that, and your emails will hit inboxes consistently and win the trust and respect of those who read them.

Inbox or Spam Folder? We'll Make Sure It's Not a Gamble. 1827 Marketing combines strategic content and marketing automation to keep your emails compliant and converting.

References and Further Reading

Gmail Yahoo email authentication requirements 2024

Source	Description
MarTech	Bulk email restrictions from Google, Yahoo and Microsoft
PowerDMARC	Google And Yahoo Email Authentication Requirements 2024
Action Network	February 2024 Gmail and Yahoo Authentication Requirements
Proofpoint	DMARC Policy & Setup Requirements for Google & Yahoo Email
Google	Gmail introduces new requirements to fight spam
dmarcian	Understanding Gmail and Yahoo DMARC Requirements

Gmail bulk sender requirements FAQ

Source	Description
Google Support	Email sender guidelines FAQ - Google Workspace Admin Help
Google Support	Email sender guidelines - Google Workspace Admin Help

Microsoft email authentication requirements 2025

Source	Description
Microsoft	Strengthening Email Ecosystem: Outlook's New Requirements
Cheapsslweb	Microsoft's New Email Authentication Rules (May 2025)

Gmail spam rate threshold requirements

Source	Description
Google Support	Email sender guidelines FAQ
Google Support	Email sender guidelines
Microsoft	Strengthening Email Ecosystem
Google Support	Email sender guidelines - Gmail Help
Cheapsslweb	Microsoft's New Email Authentication Rules
EasyDMARC	Microsoft Outlook New Email Sender Requirements
PowerDMARC	Google And Yahoo Email Authentication Requirements
Postmark	Your 2024 guide to Google and Yahoo's requirements
Proofpoint	DMARC Policy & Setup Requirements
CSO Online	Google, Yahoo announce new email authentication requirements

One-click unsubscribe RFC 8058 requirements

Source	Description
Google Support	Email sender guidelines - Google Workspace Admin Help
Google Support	Email sender guidelines - Gmail Help
Yahooinc	Sender Best Practices
PowerDMARC	Google And Yahoo Email Authentication Requirements
Google	Gmail introduces new requirements to fight spam
dmarcian	Understanding Gmail and Yahoo DMARC Requirements

List-unsubscribe header RFC 8058

Source	Description
Google Support	Email sender guidelines FAQ
Mailgun	What is RFC 8058? How Does it Enable One-click Unsubscribe?
Customer.io	Custom Unsubscribe Links: staying compliant with RFC 8058
Google Support	Email sender guidelines
Paved Blog	Bulk Sending Requirements for 2025
PowerDMARC	Google And Yahoo Email Authentication Requirements
Postmark	Your 2024 guide to Google and Yahoo's requirements
Google	Gmail introduces new requirements

Microsoft Outlook authentication requirements May 2025

Source	Description
Microsoft	Strengthening Email Ecosystem
Proofpoint	Microsoft's New Email Authentication Requirements
Braze	Outlook's new email requirements
dmarcian	Microsoft Enforces SPF, DKIM, DMARC

Email marketing ROI statistics 2024

Source	Description
Porch Group Media	100 Compelling Email Statistics for 2025
Omnisend Blog	Email Marketing Statistics 2025: Key Insights
HubSpot	2025 Marketing Statistics, Trends & Data

Percentage emails opened mobile devices 2024

Source	Description
AudiencePoint	What Percentage of Emails Are Opened on Mobile in 2024?
HubSpot	20 Mobile Email Marketing Stats
TrueList	Mobile Email Statistics 2025

B2B email marketing effectiveness statistics

Source	Description
OptinMonster	40+ Email Marketing Statistics You Need to Know for 2025
Content Marketing Institute	B2B Content Marketing Benchmarks

B2B decision makers stakeholders average

Source	Description
HubSpot	The Average Number of Customer Stakeholders Is Higher Than Ever
Challenger Inc	More B2B Decision Makers Are Weighing In
The CMO	B2B Decision Makers: How To Identify And Engage Them

Gmail Yahoo email client market share

Source	Description
Oberlo	[Most Used Email Clients Worldwide Oct 2024 Update]
DemandSage	Gmail Statistics 2025 – Users & Market Share
Statista	Global e-mail client market share 2024

Average emails received per day 2024

Source	Description
Altitude Marketing	'121 Emails Per Day': How to Use Statistics
Campaign Monitor	How many emails does the average person receive per day?
Campaign Monitor	Triggered Email Best Practices

Microsoft Exchange Online email limits 2025

Source	Description
Microsoft	Microsoft Tech Community - Latest Blogs
Microsoft	Exchange Online to introduce External Recipient Rate Limit
Microsoft	Introducing Exchange Online Tenant Outbound Email Limits

Microsoft ERR implementation timeline

Source	Description
Microsoft	Strengthening Email Ecosystem
QED web design	[NEW: Microsoft Outlook Authentication Requirements 2025]

SPF RFC 7208 verification

Source	Description
IETF Datatracker	RFC 7208 - Sender Policy Framework (SPF)
Tech-invite	RFC 7208 (Apr 2014, Proposed STD, 64 pages)
Wikipedia	Sender Policy Framework

Email deliverability best practices

Source	Description
Email on Acid	Email Deliverability Best Practices
MarTech	Bulk email restrictions guide
Leadrebel Blog	Improve Email Deliverability

One-click unsubscribe implementation

Source	Description
MailerLite	A simple guide: List-unsubscribe header
Arial Software	Understanding Gmail One-click & RFC8058
Yahoo Finance	Meeting Google and Yahoo's Requirements

Microsoft enforcement policy updates

Source	Description
Proofpoint	Microsoft's New Email Authentication Requirements
Mailgun	Microsoft Outlook sender requirements 2025
dmarcian	Microsoft Enforces SPF, DKIM, DMARC

Authentication protocol technical details

Source	Description
Cloudflare	What are DMARC, DKIM, and SPF?
Mimecast	SPF vs. DKIM vs. DMARC: A Guide
TechTarget	SPF, DKIM and DMARC: What are they

Email Standards and Requirements

Source	Description
BuzzStream	New Google and Yahoo Email Requirements for 2024
Yahoo Help	Bulk email industry standards
Yahoo Sender Hub	FAQs