How will migrating ESP affect Google and Yahoo enforcement of new email sender requirements?
Matthew Whittaker
Co-founder & CTO, Suped
Published 29 Jun 2025
Updated 17 Aug 2025
8 min read
Migrating to a new Email Service Provider (ESP) is a significant step for any sender. It promises new features, better performance, or cost efficiencies. However, with Google and Yahoo's new email sender requirements now in full effect, the timing and execution of such a migration have become even more critical. These updates, focusing heavily on email authentication, spam rates, and easy unsubscription, mean that any transition needs careful planning to avoid impacting your deliverability.
The primary concern during an ESP migration, especially under these new guidelines, is maintaining your sender reputation. Mailbox providers like Google and Yahoo rely on your historical sending behavior to determine if your emails should reach the inbox or be sent to spam. A sudden change in sending infrastructure or practices without proper adherence to new rules can be flagged as suspicious, leading to significant deliverability issues.
The question of whether to migrate before or after the enforcement dates (which largely began in February 2024) is a valid one. While some believe waiting might reduce variables, others argue that adhering to new sender requirements is essential regardless of your ESP. The key lies in understanding how your new ESP supports these requirements and how your migration plan integrates with them.
Understanding the new requirements
The new requirements from Google and Yahoo fundamentally reshape the landscape for bulk email senders. They are not merely suggestions but mandatory standards aimed at curbing spam and enhancing user trust. These requirements primarily revolve around three pillars:
Email authentication: Senders must implement strong email authentication protocols such as SPF, DKIM, and DMARC. This verifies the legitimacy of your emails and prevents spoofing and phishing.
Spam rate threshold: Senders must keep their spam complaint rates exceedingly low, specifically below 0.3% (and ideally below 0.1% for Gmail). High spam rates are a direct indicator of poor sending practices and will lead to inbox placement issues.
Easy unsubscription: Bulk senders must implement a one-click unsubscribe mechanism in their emails and process unsubscribe requests within two days. This enhances user control and reduces unwanted email, which in turn can lower spam complaints.
These requirements apply to any domain sending a significant volume of email, typically defined as over 5,000 emails per day to Gmail or Yahoo addresses. If you are migrating ESPs, your new platform must support these standards, and your DNS records must be correctly configured to reflect the change. Failing to do so can result in your emails being deferred or even outright rejected.
Key enforcement areas for bulk senders
Authentication: Google and Yahoo require SPF, DKIM, and DMARC alignment for all bulk senders.
Spam rate: Maintain a spam complaint rate below 0.3% to avoid deliverability penalties.
When migrating to a new ESP, you generally have two main approaches: a clean cut or a gradual warm-up. A clean cut involves switching all sending to the new ESP at once. While simpler from a management perspective, it carries higher deliverability risks, especially with new enforcement rules.
A gradual warm-up, on the other hand, involves slowly increasing sending volume through the new ESP while maintaining some sending from the old one. This allows you to build a new sender reputation on the new IP addresses and domains (if applicable) over time. This approach significantly reduces the risk of being flagged by spam filters and helps maintain consistent inbox placement during the transition. It’s generally the recommended strategy for managing email deliverability during an ESP migration.
The timing of your migration relative to the enforcement date matters less than the thoroughness of your preparation. If your new ESP is fully compliant and you meticulously follow a warm-up schedule, moving forward with migration should be fine. The complexities often arise from managing two systems concurrently, not from the enforcement itself, as the requirements are universally applied regardless of your provider.
Clean cut migration
Process: Switch all sending traffic to the new ESP at once after initial setup.
Reputation risk: Higher risk of sudden deliverability drops due to new IP reputation, especially with Google and Yahoo's stricter rules.
Management: Simpler management as you only focus on one platform after the switch.
Gradual warm-up
Process: Slowly increase sending volume on the new ESP while phasing out the old.
Reputation benefits: Allows for gradual IP warming and building a solid sender reputation with mailbox providers.
Management: Requires careful synchronization of data and metrics between both ESPs during the transition.
Technical considerations during ESP migration
The backbone of email deliverability, especially under the new Google and Yahoo requirements, rests on proper email authentication. This means correctly configuring your SPF, DKIM, and DMARC records for your sending domain. When you migrate ESPs, these DNS records must be updated to reflect your new sending infrastructure.
Your new ESP will provide specific DNS entries that need to be added or modified in your domain's DNS settings. This includes SPF records to authorize your new ESP's sending IP addresses, DKIM keys for digital signing, and potentially DMARC record updates to point to the new ESP's aggregate reporting. It's crucial to ensure these are configured correctly before you start sending emails through the new platform. A common point of failure is neglecting to update your return-path, also known as the bounce address, to align with your new ESP.
Many modern ESPs, including Keap, have proactively made adjustments to support the Google and Yahoo changes, often including options for custom return paths to ensure proper alignment. This greatly simplifies the process. However, the responsibility for implementing these DNS changes accurately still rests with the sender. For a deeper dive into these requirements, see our guide on DMARC, DKIM, and SPF updates.
Monitoring and maintaining reputation post-migration
Regardless of your migration strategy, continuous monitoring of your email performance is non-negotiable, especially with the new enforcement rules. Key metrics to watch include your spam complaint rate, bounce rate, and delivery rate. Google and Yahoo's emphasis on low spam rates means you must be vigilant.
Leverage tools like Google Postmaster Tools and Yahoo's Sender Hub to track your domain's reputation and compliance status directly with these major mailbox providers. These platforms provide invaluable insights into your deliverability performance, allowing you to identify and address issues promptly. Pay close attention to any warnings or shifts in your reputation score.
Furthermore, regularly checking for your domain or IP addresses on email blocklists (or blacklists) is crucial. Getting listed on a blocklist can severely impact your deliverability across all providers. Tools designed for blocklist monitoring can alert you quickly if your reputation takes a hit, enabling you to take corrective action swiftly, such as requesting delisting or adjusting your sending practices.
Metric
Why it matters
Target threshold (Google/Yahoo)
Spam complaint rate
Directly impacts sender reputation; high rates lead to blocks.
Below 0.3% (ideally below 0.1%)
Delivery rate
Indicates if emails are reaching inboxes or being deferred/bounced.
High (aim for 98%+) without soft bounces
Bounce rate
High rates suggest poor list hygiene or technical issues.
Keep low (below 2-3%)
Views from the trenches
Best practices
Ensure your new ESP has clear documentation and support for Google and Yahoo's new email sender requirements.
Verify that all DNS records (SPF, DKIM, DMARC) are correctly updated and propagated for your sending domain.
Implement a slow and steady warm-up plan for any new IP addresses or sending domains used by your new ESP.
Actively monitor your sender reputation and deliverability metrics using postmaster tools and DMARC reports.
Clean your email list thoroughly before migration to remove unengaged or invalid addresses, reducing potential spam complaints.
Common pitfalls
Abruptly switching all sending volume to a new ESP without a proper warm-up period, leading to deliverability issues.
Failing to update all necessary email authentication records for the new ESP, causing DMARC failures.
Ignoring spam complaint feedback loops, resulting in sustained high spam rates that trigger blocklists (blacklists).
Not having a clear plan for synchronizing unsubscribe requests and bounce data between old and new ESPs during transition.
Overlooking the new one-click unsubscribe requirement, which can lead to negative user experience and penalties.
Expert tips
Leverage the migration as an opportunity to reassess and strengthen your email list hygiene practices.
Consider using a DMARC monitoring service to gain comprehensive visibility into your email authentication status and potential threats.
Engage with your new ESP's deliverability team early in the migration process for tailored advice and support.
Prepare a rollback plan in case unexpected deliverability issues arise after the migration.
Educate your team on the new Google and Yahoo requirements to ensure ongoing compliance.
Marketer view
Marketer from Email Geeks says that some ESPs, like Keap, have already implemented necessary DNS improvements, including custom return paths, to align with the latest Google and Yahoo mandates.
Dec 28, 2023 - Email Geeks
Marketer view
Marketer from Email Geeks says that the enforcement of new requirements primarily relies on DKIM domain alignment, and a single DKIM domain can be utilized across multiple ESPs.
Dec 28, 2023 - Email Geeks
Final thoughts on ESP migration and compliance
Migrating your ESP does not necessarily require you to wait until after Google and Yahoo's enforcement of new email sender requirements. The critical factor is how well your migration plan aligns with these new rules, which are essentially a formalization of long-standing email best practices. If your chosen ESP supports all the necessary authentication and compliance features, and you execute a careful, gradual warm-up, you can proceed with confidence.
The potential impact of these new requirements on your deliverability during migration is significant if not handled correctly. Improper DNS setup, neglecting authentication protocols, or failing to manage spam rates can lead to emails being blocked or sent to the junk folder. Therefore, thorough preparation and diligent monitoring are paramount.
Ultimately, the decision to migrate ESPs should be based on a comprehensive assessment of your readiness and your new ESP's capabilities. Focus on ensuring compliance with all Google and Yahoo mandates, regardless of when you make the switch. This proactive approach will safeguard your email deliverability and help your messages consistently reach the inbox.
Google and 
Yahoo require SPF, DKIM, and DMARC alignment for all bulk senders.
Keap, have proactively made adjustments to support the Google and Yahoo changes, often including options for custom return paths to ensure proper alignment. This greatly simplifies the process. However, the responsibility for implementing these DNS changes accurately still rests with the sender. For a deeper dive into these requirements, see our guide on DMARC, DKIM, and SPF updates.
