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Posted At: Mar 19, 2026 - 445 Views

Gmail Tightens Its Sender Rules in 2026: What Shopify and PrestaShop Merchants Need to Check

Since November 2025, Gmail has been gradually stepping up enforcement of its rules for non-compliant senders. According to Google's official FAQ, messages that don't meet the requirements may be delayed, marked as spam, or temporarily or even permanently rejected, depending on the issue detected. For Shopify and PrestaShop stores that send transactional and marketing emails, this makes the technical setup of the sending domain and the quality of the contact list even more critical.

What Has Actually Changed Since November 2025

Since November 2025, Google has been ramping up enforcement on non-compliant traffic in a gradual, progressive way — not an immediate, total block, but an escalation based on the severity of the issue.

These Gmail enforcement requirements apply to emails sent to personal Gmail accounts, not to messages received by Google Workspace accounts.

Microsoft has moved in the same direction. Since May 5, 2025, Microsoft officially requires domains sending more than 5,000 emails/day to Outlook.com, Hotmail and Live.com to comply with SPF, DKIM and DMARC. Non-compliant messages are first sent to the Junk folder, then potentially rejected if the problem persists.

The Rules to Follow: What Applies to Whom

For all senders to personal Gmail accounts, Google's minimum requirements are:

  • SPF or DKIM configured
  • Valid PTR record (reverse DNS of the sending IP matching the domain)
  • TLS for message transport
  • Compliance with the RFC 5322 format
  • Spam rate kept under control

For bulk senders (roughly 5,000 emails/day or more to personal Gmail accounts), Google requires SPF and DKIM, a DMARC record with alignment of the From: domain, and a one-click unsubscribe link for marketing emails, with unsubscribes processed within 48 hours.

On spam rate, Google is precise: the goal is to stay below 0.10% and avoid reaching 0.30% or higher, the threshold at which the risk of rejection rises sharply.

Why This Is Critical for E-commerce Merchants

A Shopify or PrestaShop merchant sends emails constantly: order confirmations, abandoned cart reminders, promotions, newsletters. If your domain isn't properly configured, your messages may be delayed, marked as spam or rejected — before they even reach their destination.

But technical setup alone isn't enough. A contact list loaded with invalid addresses, spam traps or disposable emails inevitably drives up your complaint rate and damages your sending reputation — even with SPF, DKIM and DMARC perfectly in place.

That's exactly what GTMailHygiene for Shopify and MailHygiene PRO for PrestaShop do: they detect risky addresses before they hurt your deliverability. If you need to check a CSV file of addresses outside of any platform, GTMail-Verif does it directly online.

What You Need to Check Now

  1. Does your domain have SPF, DKIM and DMARC? → Check on MXToolbox
  2. Is your complaint rate below 0.10%? → Check Google Postmaster Tools
  3. Does your list contain invalid, disposable or inactive addresses? → Clean it with GTMailHygiene (Shopify), MailHygiene PRO (PrestaShop) or GTMail-Verif

The Bottom Line

Gmail and Microsoft have both crossed the line into actually enforcing their rules. For an online merchant, the impact is direct: emails blocked or filtered as spam = missed orders, uninformed customers and a domain reputation that degrades over time.

Before your next campaign, check your email authentication and clean your contact list to limit bounces, spam complaints and deliverability losses.

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