Recently, Google has intensified its filtering criteria for emails in Gmail, specifically targeting newsletters lacking DKIM authentication. This development means that emails without this digital signature are more often automatically classified as spam or relegated to secondary categories, even if they come from legitimate senders.
Gmail no longer lets unsigned newsletters through
Since the update of its anti-spam filters, Gmail pays much stricter attention to DKIM authentication (DomainKeys Identified Mail). Previously, a message without a DKIM signature could sometimes be accepted in the main inbox, especially if it came from a sender recognized in the user’s history. Now, these emails are more frequently redirected to the spam or promotions folder.
This reinforcement is part of a strategy to reduce unwanted emails, but it also affects established newsletters that do not use DKIM or have incorrect configurations. According to reports from email marketing professionals, this change can cause the inbox placement rate to drop from 70 to 85% for unsigned emails compared to properly authenticated ones.
What is DKIM authentication and why does it matter now?
The DKIM signature is a process by which a sending server digitally signs each message using a public key linked to the domain. This allows the receiving server to verify that the email has not been altered in transit and that it indeed comes from the indicated domain.
Before this reinforcement, Gmail relied on several signals to decide where to place a message: user engagement, conversation history, sender reputation, etc. Now, the absence of DKIM becomes a much more significant criterion in the evaluation, to the point where a perfectly structured but unsigned message has a significantly higher probability of being filtered.
Who is most affected by this change?
The entities most affected are often:
- Small businesses or freelancers using simple sending solutions,
- Newsletters managed via basic email services without advanced configuration,
- Automated emails generated from internal systems without DKIM signature.
A survey conducted among 1,200 email marketing managers indicates that nearly 48% of them do not yet have a fully operational DKIM configuration for all their mailing lists. Among these cases, the vast majority have noticed a drop in open rates on Gmail since the introduction of the reinforced criteria.
How does Gmail now evaluate your message?
Gmail’s email processing relies on several chained filters. Now, within the process:
- Authentication verification: DKIM is checked as a priority.
- Check of other criteria: SPF, DMARC, domain reputation.
- Analysis of engagement behavior: open rates, interactions.
- Final placement decision: main inbox, promotions, spam.
An unsigned newsletter risks being automatically classified as less reliable, even if all other elements are compliant. This means that a message may never reach the main tab, significantly reducing its chances of being seen quickly by the recipient.
Consequences for open and conversion rates
For a newsletter, the open rate is one of the major performance indicators. Automatic relegation to a secondary tab or spam folder can significantly lower this rate. Internal studies from emailing platforms show that:
- DKIM-authenticated messages show 10 to 30% higher open rates than unsigned ones,
- Unsigned messages have more than a 50% chance of landing outside the main inbox.
These variations can lead to a notable decrease in clicks, conversions, and responses, as many recipients rarely explore their secondary or spam folders.
How to enable DKIM for your newsletters?
Most professional emailing services (Mailchimp, Sendinblue, HubSpot, etc.) offer DKIM activation in their domain settings. This generally involves:
- Accessing your domain’s DNS management,
- Adding a TXT entry provided by your sending platform,
- Waiting for DNS propagation (sometimes a few hours),
- Verifying success via a signature test tool.
Once DKIM is configured, each sent message carries a digital signature that allows Gmail to verify its authenticity before placement. This improves the trust granted to the message by the service’s filters.