October 6, 2023

Navigating the new email Sender requirements: A guide to Google and Yahoo's latest updates

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🖱️ Gmail and Yahoo updated email guidelines: What you need to know

This week, Google and Yahoo announced new Sender guidelines for users sending to their platforms. To help ease the bouncing between documentation and updated guidelines from Google and Yahoo, we created this guide to help!

With billions of emails exchanged daily, platforms like Google and Yahoo continually refine their guidelines to enhance the email experience for both senders and recipients.

This article delves deep into the updated email guidelines released by these email giants. Here's what we'll cover:

  • Who is Impacted?
  • Timeline for implementation.
  • Opt-in methods.
  • Handling unsubscribes.
  • Spam Rate requirements..
  • Authentication methods and policies.
  • Infrastructure configuration.
  • Message formatting.
  • Inactive recipients and bouncing.
  • Affiliate Marketing.
  • Additional practices.
  • Questions we've got.

Whether you're an email marketing professional, a business owner or simply an individual curious about these updates, this comprehensive guide will shed light on what Google and Yahoo expect from senders in 2024 and beyond.

📧 Who is impacted?

Gmail: The updated guidelines impact “all senders”. However, for those dispatching over 5,000 messages daily to Gmail accounts, there are additional requirements to take note of.

Yahoo: The updated guidelines appear to be applicable to “all senders”. Notably, there's no specific mention of volume thresholds that would necessitate additional guidelines. The only mention of a volume was in the announcement where it reads: “In the first quarter of 2024, we will require that all bulk senders:…” with the following requirements, but no definition of “bulk”.

⏲️ What’s the timeline for implementation?

Gmail: Senders should mark their calendars for February 1, 2024. That's the official start date for Gmail's guidelines, though the platform encourages implementing these changes even before that, noting: “Meeting the sender requirements before the deadline may improve your email delivery. If you don’t meet the requirements described in this article, your email might not be delivered as expected, or might be marked as spam.”

Yahoo: In the first quarter of 2024, Yahoo will begin enforcing its updated email standards.

👋 Opt-in methods: Who can you email?

Gmail and Yahoo's stance is clear: Only send emails to those who have indicated they want to hear from you.

Gmail: Recommends sending only to those who “want to get messages from you”. Purchasing email addresses or mailing lists is not cool, and auto-checked opt-in forms are a no-go. Importantly, they note, “Some countries and regions restrict automatic opt-in. Before you opt-in users automatically, check the laws in your region.”

Yahoo: Their guidelines parallel Gmail's, emphasizing emailing only those who have “specifically requested it”. Like Gmail, buying email addresses is discouraged, and they echo the caution about pre-checked opt-in forms.

Confirmation methods

Gmail: They mention confirming each recipient's email address before adding them to your list. This ensures you're only communicating with genuine, interested parties.

Yahoo: They advise sending new subscribers an email asking them “to click to confirm their opt-in”. The idea is that this process “will improve the experience for users (who won't sign up accidentally or get signed up maliciously) and for your list (which won't contain uninterested people, fake email addresses, or most robots).”

Side note: The idea of double opt-in or sending a confirmation email alongside things like invisible reCAPTCHA are a topic we can dig into further in another article. It’s confusing if these are requirements moving forward, or more like suggestions or recommendations.

🤔 How to handle unsubscribes

Guidelines from both Gmail and Yahoo mention the ability to one-click unsubscribe and processing unsubscription requests within two days. It remains ambiguous if this period is two business days or two consecutive days.

Google states: "…we’re requiring that large senders give Gmail recipients the ability to unsubscribe from commercial email in one click, and that they process unsubscription requests within two days."

Echoing this sentiment, Yahoo declares: “We will require senders to support one-click unsubscribe and honor our users requests within two days.”

Yet, a crucial aspect that arises here is the role of Preference Centers.

Google expressly mentions, “Let recipients review the individual mailing lists they’re subscribed to. Let them unsubscribe from lists individually, or all lists at once.”

This puts forward a pressing question: Does redirecting to a Preference Center qualify as adhering to the one-click unsubscribe criterion? Or is it mandated that a mere click on "unsubscribe" should suffice for the user?

Another factor to consider is the impact of email bot clicks on this process, and the potential of inadvertent unsubscribes.

Further deepening this exploration, both Google and Yahoo highlight “List-Unsubscribe”, referencing documentation from RFC 2369 and RFC 8058 (Criteria for senders to appear in the Subscription hub for Yahoo users, or to set up one-click unsubscribe for Gmail messages).



Side note: It’s unclear how it would work if you left out the “List-Unsubscribe” URL, or the second bullet point in the screenshot. How would they know where to send the request?



Additional note: Yahoo also points towards the Messaging Anti-Abuse Working Group’s Sender Best Communications Practices Version 3.0 for more sender best practices. An intriguing point from this document states, “When a subscriber is presented with a hyperlinked online subscription preference center that includes multiple subscription options, the unsubscribe option should be pre-checked by default for the user’s currently subscribed lists.” This is certainly food for thought, especially given the ongoing discussions on user preferences and unsubscription processes.

🔁 Navigating Spam Rate requirements: Google and Yahoo's guidelines

Both Google and Yahoo have specified guidelines on how to manage and maintain acceptable spam rates. But they haven't just set the rules and left senders to their own devices — both platforms offer specific tools to help in the monitoring and management of these metrics.

Google: The platform has set precise benchmarks, instructing senders to "Keep spam rates reported in Postmaster Tools below 0.3%" and to “Aim to keep your spam rate below 0.10%”. It's noteworthy that to access these metrics, senders will need to sign up for Postmaster Tools, a separate service provided by Google.

While the official "Email sender guidelines" don't delve into "Feedback Loop", other Google documentation does. The FeedBack Loop (FBL) is particularly aimed at high volume senders, allowing them to identify campaigns with high complaint rates. Importantly, the Postmaster Tools FBL dashboard will report any campaigns with an "unusual spam rate" that could cause deliverability issues.

Side note: FBL data will only pertain to recipients.

Yahoo: The spotlight is Complaint Feedback Loop, or their CFL program.

Not only does this help senders keep track of their spam complaint rates, but when a message signed with a DKIM key enrolled in the CFL program draws a complaint, Yahoo sends the sender an informative report. This report, rendered in the Abuse Reporting Format (ARF), enables the sender to suppress that recipient from future campaigns, further assisting in maintaining a lower spam rate.

Conclusion: Both Gmail and Yahoo are taking steps toward curbing spam and ensuring a better inbox experience for users. By providing tools like Postmaster and CFL, it's evident that these platforms are championing a proactive approach, urging senders to take initiative, get some data, use their tools. The goal and collective push towards making inboxes “less spammy” for readers, but also creating a more reputable email marketing landscape.

✅ Authentication methods and policies: SPF, DKIM and DMARC

Both Google and Yahoo underscore the importance of email authentication to ensure the credibility of senders. They recommend setting up SPF, DKIM and DMARC for optimum email delivery.

Let's delve into their specific guidelines:

SPF (Sender Policy Framework)

SPF is like a whitelist for email servers. It specifies which servers are authorized to send emails on behalf of a domain, helping to prevent email spoofing and phishing.

Google: Emphasizes publishing a record listing all email senders for the domain.

Yahoo: Stresses the importance of publishing valid SPF records for domains.

DKIM (DomainKeys Identified Mail)

DKIM adds a digital signature to email messages, allowing the recipient's server to verify that the message was sent by an authorized sender and hasn't been modified during transit.

Both Google and Yahoo mention authenticating email with DKIM. However, Google specifies a minimum key length of 1024 bits, but 2048-bit is recommended.

DMARC (Domain-based Message Authentication, Reporting and Conformance)

DMARC builds on SPF and DKIM. It tells email receivers how to handle emails that fail authentication checks (For example: reject or quarantine) and provides reporting to domain owners about email authentication results.

Google: For senders dispatching over 5,000 messages daily, DMARC is a requirement, but Google recommended setting up DMARC regardless. The platform notes that while a domain needs to pass either SPF or DKIM (preferably both), it's also crucial to ensure messages are authenticated, lest they be marked as spam or rejected with a 5.7.26 error.

If using an email service provider, they advise ensuring the domain’s email is authenticated with both SPF and DKIM.

Even though Google is shifting towards a DMARC quarantine enforcement policy for all senders, they mention that the DMARC enforcement policy can be set to "none."

Yahoo: Strongly urges senders to publish a DMARC policy for every domain that dispatches emails.

Additional notes

Google recommends setting up ARC for domains that forward emails regularly.

ARC stands for "Authenticated Received Chain." It's an email authentication protocol designed to help verify the authenticity of email messages as they pass through intermediaries, such as forwarding services and mailing lists.

ARC allows email senders to sign and secure their messages with cryptographic signatures, even when the messages traverse multiple email servers. This helps in maintaining the integrity of email authentication (SPF, DKIM, and DMARC) throughout the forwarding process, reducing the chances of messages being marked as fraudulent or phishing attempts. ARC helps improve email security and deliverability in complex email forwarding scenarios.

🚧 Infrastructure configuration

Both Google and Yahoo emphasize the importance of publishing valid reverse DNS (PTR) records for sending IPs or domains.

Why is this important?

Proper reverse DNS setups can reduce the chances of emails getting flagged as spam by email service providers. Google specifically emphasizes that the sending IP address should match the IP address of the hostname detailed in the DNS pointer record, aka PTR.

Yahoo suggests that the reverse DNS should reflect your domain name in some way, and not to use a reverse DNS that looks like a “dynamically-assigned IP instead of a static mail server,”

What about shared IPs?

When multiple email senders utilize the same IP address, it's known as a shared IP setup. While using shared IPs can be cost-effective, it comes with its own challenges.

The email activity and reputation of any sender using that shared IP address can impact everyone else on it. So, if one sender gets flagged for spammy behavior, it might affect the deliverability rates of all other senders sharing that IP.

Google mentions it’s ideal to send all messages from the same IP address. However, if circumstances necessitate sending from multiple IPs, they suggest allocating a different IP address for each type of message. Yahoo resonates with this sentiment.

Why different IPs for different email types?

The rationale behind this is building and maintaining a solid sender reputation.

By organizing email types by IP, if one category of email (like promotional emails) gets flagged, it doesn't impact the reputation of other categories, ensuring their deliverability remains unaffected.

For clarity, Google provides these examples:

  • Use one IP address for sending account notifications.
  • Use a different IP for sending promotional messages.

Moreover, it's recommended that messages of a similar category should originate from a consistent "From:" email address. Here's an example from Google using a domain called

  • Sales receipt messages:
  • Promotional messages:
  • Account notification messages:

Backing this, Yahoo advises: "Don't send bulk/marketing email from the same IPs you use to send user mail, transactional mail, alerts, etc."

🎨 Message formatting

Emails are not just about the content you type out. The way they're formatted matters significantly, especially when sending to major providers like Google (Gmail) and Yahoo.

These platforms have specific guidelines on message formatting to ensure transparency, user-friendliness and security.

RFC compliance: The foundational standards

Both Google and Yahoo stress compliance with RFC 5322, which is titled "Internet Message Format." This standard provides specifications for the format of email messages. Yahoo adds another layer by insisting emails comply with RFC 5321, the "Simple Mail Transfer Protocol." This protocol dictates how emails are transmitted over the internet.

Hidden content: Logic vs. visibility

Both platforms mention a guideline that can seem ambiguous: "Don’t use HTML and CSS to hide content in your messages." This likely pertains to techniques that intentionally hide content from the end-user for deceptive purposes.

Conditional logic, like displaying content based on a user's device, is a different matter and is generally used to enhance user experience.

We are unsure and have this listed as an open question to discuss further.

From Headers: Keep it simple

A clear guideline from both platforms is about the "From" headers in email messages. The directive is straightforward: include only one email address.

This clarity ensures users know precisely who the message is coming from, adding a layer of trust.

Additional formatting guidelines

Message subject and Sender info

Both platforms emphasize clarity. The subject should be representative of the email's content, and the sender's details should be transparent.

Links in Messages

While Google advises that web links in messages should be "visible and easy to understand,"

Yahoo doesn’t specifically mention web links, but it seems that the underlying principle across the guidelines are the same: clarity and honesty.

Content consistency

Google advises against mixing different types of content in the same message. For example, promotional content shouldn't be embedded within a sales receipt message.

Message Header size

While explicitly mentioned by Google, keeping message headers from being excessively large is likely good practice across all platforms.

🧟 Inactive recipients and bouncing: Keeping your list clean

Digital mailboxes, like their physical counterparts, don't have infinite space.

Both Google and Yahoo have emphasized this in their guidelines, urging senders to be mindful of inactive recipients and bounced messages.

Identifying inactive recipients

The term "inactive" isn't clearly defined by either platform, suggesting it's up to the sender's discretion.

However, the overarching principle is clear: Send messages to folks who want to receive messages from you.

While the specific duration that makes a recipient "inactive" might vary, common metrics to gauge engagement include email opens, clicks or conversions. Measuring engagement can be challenging in the modern email landscape, but they can provide some insight and directional information that can help.

Addressing bounces

Repeatedly sending messages to bouncing addresses can hurt your sender reputation. It’s advised to remove recipients after multiple bounces, ensuring that you're not repeatedly trying to reach non-existent or error-ridden addresses.

The bigger picture

Regularly pruning your list isn't just about adhering to platform guidelines. It's about maintaining the health and effectiveness of your email campaigns. Inactive or bouncing addresses can skew metrics, hinder deliverability and increase costs.

Sunset or Reengagement flows

If you notice a portion of your subscribers showing decreased activity or engagement, consider implementing Sunset or Reengagement campaigns.

These initiatives aim to reengage subscribers, or to smoothly remove them from your list, ensuring your content reaches an active and interested audience consistently.

🤝 Affiliate Marketing

Affiliate marketing, while a strategy for broadening reach and increasing conversions, is not without its potential challenges, especially when viewed from the lens of major email platforms.

Google's note on Affiliate Marketing

Google acknowledges the inherent benefits of affiliate marketing programs, which can reward companies or individuals for driving traffic to your website. However, they sound a note of caution. Given that affiliate marketing can, at times, be abused by spammers, Google urges email senders to stay vigilant.


Google's guidelines mention to “regularly monitor affiliates and remove any affiliates that send spam.” This not only ensures compliance with email best practices but also safeguards the reputation of your brand.

➕ Additional practices

While most guidelines above fall more neatly into categories, both Google and Yahoo have highlighted certain practices that might seem additional or miscellaneous, but are important to note.

Let’s delve into these additional recommendations:


  • From Header Authenticity: Avoid impersonating Gmail in the From: headers. This helps in building trust and ensuring clear sender identity.
  • Mailing list senders: If you're operating as a mailing list sender, it's recommended to include a List-id: header. This practice aids in clarity and organization for recipients.
  • Subscriber experience: An interesting point to note is that messages from an address already saved in the recipient’s contacts are less likely to be flagged as spam. It emphasizes the importance of building and maintaining genuine relationships with your subscribers.


  • Global adherence to CAN-SPAM: Yahoo underscores the importance of adhering to the CAN-SPAM Act, “regardless of where in the world you’re sending your mail”. We noted this in our open questions.
  • Respect frequency: It's important to respect the frequency with which subscribers expect to hear from you. If someone has signed up for a monthly newsletter, inundating them with daily emails can be off-putting. Yahoo specifically highlights this, stating, “Honor the frequency of the list's intent.”
  • Set clear expectations: When users subscribe to your mailing list, be upfront. Inform them about what kind of emails they can expect, how often and what it will look like — design or format. Setting clear expectations right at the onset may reduce unsubscribes and complaints.

❓️ Open questions: Decoding the ambiguities of Google and Yahoo’s new email guidelines

The newly released guidelines from Google and Yahoo, while comprehensive, do leave some room for interpretation. We've put together a list of our open questions based on the guidelines and our initial analysis:

Sender volume-related concerns

  • Definition of "bulk senders": Yahoo mentions requirements for "bulk senders" set to begin in 2024. But what qualifies someone as a bulk sender? Is it volume-based or are other metrics involved?
  • Volume Thresholds: Google's guidelines mention added requirements for senders dispatching over 5,000 messages daily to Gmail users. What if a sender's volume fluctuates around this threshold?

Unsubscribe mechanics

  • Understanding "Two Days": When Google and Yahoo speak of a two-day window for processing unsubscription requests, does this encompass business days only, or does it include weekends?
  • Preference Centers: How do these align with the concept of a one-click unsubscribe? Is redirecting users to a Preference Center in line with this one-click protocol?
  • Email bots' impact: Given the automated nature of email bots, there's potential for them to trigger inadvertent unsubscribes. How do the new guidelines account for such scenarios?

Content visibility and user experience

  • Hidden content clarification: The guidelines advise against using HTML/CSS to "hide content." Does this only pertain to content visibility, or does it also extend to conditional logic techniques?
  • Double opt-in: Is there a push towards making double opt-in or confirmation emails a standard requirement for sign-ups?

Regulatory and compliance implications

  • Geographical scope: Yahoo references the CAN-SPAM Act, but does this mean the guidelines are U.S.-centric? How do they mesh with global policies like GDPR and CASL?
  • Repercussions for non-compliance: What are the repercussions for not adhering to these guidelines? Deliverability issues?
  • Notifications: If a sender falls short of the guidelines, will Google or Yahoo provide any proactive alerts or feedback?

Marketing and Partnership

  • Affiliate Marketing: For those involved in affiliate programs, are there recommended tools or strategies to ensure compliance with the guidelines?

General Enforcement

  • Guideline vs. rule: Some guidelines touch on areas like message formatting and managing inactive subscribers. Is the intention to merely suggest best practices or to enforce them strictly with potential repercussions?

It's important for senders to be aware of these open questions and to stay updated. As with all new guidelines and policies, clarifications and further details will likely be released as the implementation date nears. Always be proactive and monitor for updates to ensure your email practices are compliant and effective.

🎁 Wrapping up

The Newsletter Newsletter

At first glance, Google and Yahoo's updates might not seem revolutionary. In fact, they reflect practices that senders should ideally have already been implementing. But given their expansive user base and influence on global email traffic, these companies' policies can play a pivotal role in shaping the future of email.

For many, the guidelines reiterate a known truth: Quality, user-centered communication should be at the heart of every email. Yet, it often takes giants like Google and Yahoo to truly catalyze change on a global scale.

Taking a step further, platforms like are reimagining email altogether.

Their approach, from screening emails as one would screen calls, to categorizing newsletters into a dedicates space called “The Feed," and even allowing for collaborative email handling through "Extensions," challenges our conventional email interactions. Features like "The Paper Trail" for receipts and "HEY Spam Corps" for improved spam detection highlight an innovation-driven vision.

HEY’s holistic approach to email not only offers solutions to age-old email pain points but also redefines what an email experience can be. It's not just about sorting and reading messages; it's about user empowerment and curated content consumption.

In conclusion, while big players like Google and Yahoo are refining the rules to elevate email's integrity, others like are pushing boundaries, offering glimpses into the next era of email communication. As senders and receivers, it’s on us to stay informed, adapt and be proactive.

Remember, these guidelines aren't just about technicalities. They echo a broader shift towards more authentic, user-centric digital communication.

Embrace the change, and use it as an opportunity to refine your email strategy, ensuring that every message you send adds value to its recipient.

Want us to deep dive on a newsletter? Or maybe feature your newsletter in an upcoming newsletter? Email us.

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