In 2025, the main email providers — Google (Gmail), Yahoo, Microsoft (Outlook) — have further strengthened their email acceptance policies. This tightening addresses three major challenges: the fight against massive spam, the rise of email cyberattacks such as phishing and domain spoofing, and improving the user experience to ensure useful, expected, and secure content.
Businesses and professionals who practice cold emailing, newsletters, or marketing automation are directly affected by these new requirements.
Domain authentication: SPF, DKIM, and DMARC become mandatory
Domain authentication is now essential. Without these technical measures, your emails may simply never reach the inbox.
SPF (Sender Policy Framework) specifies which servers are authorized to send emails from your domain. It is a first line of defense against identity spoofing.
DKIM (DomainKeys Identified Mail) adds a cryptographic signature to emails, ensuring their integrity and that the content has not been altered.
DMARC (Domain-based Message Authentication, Reporting & Conformance) coordinates SPF and DKIM while defining a clear policy on the handling of non-compliant emails.
Since 2024, Gmail and Yahoo require the presence of a simple, visible, and accessible one-click unsubscribe link. In 2025, this obligation also applies to transactional emails. Failure to comply carries a high risk of automatic classification as spam.
Companies have a maximum of 48 hours to remove any person who clicked on this link.
Providers now closely monitor the spam complaint rate. Exceeding a threshold of 0.3% (i.e., 3 complaints per 1,000 emails sent) can result in a complete domain block.
To prevent this, you must:
Send only to qualified contacts.
Use honest and engaging email subject lines.
Regularly clean your contact list.
Here is a comparative overview of email sending platforms according to their compliance:
| Sending platform | Authentication | One-click unsubscribe | 2025 compliant |
|---|---|---|---|
| Mailchimp | Yes | Yes | ✅ |
| Sendinblue / Brevo | Yes | Yes | ✅ |
| Lemlist / Instantly | Sometimes | Yes | ⚠️ |
| Gmail / manual Outlook | No | No | ❌ |
Clean your database
A clean database is essential. Regularly delete inactive or obsolete addresses, especially those who haven’t opened your emails in over six months. This improves your engagement rates and sender reputation.
Use double opt-in
Double opt-in is a method where the recipient confirms their subscription twice: first by filling out a form, then by validating a confirmation email sent automatically. This ensures each recipient has given explicit consent to receive your emails. In 2025, this security is seen as a mark of professionalism.
Monitor your domain reputation
Don’t leave your reputation to chance. Several tools allow you to track your technical performance and compliance, such as:
Google Postmaster Tools
GlockApps
Mail-Tester
Each helps detect anomalies and adjust your campaigns.
Ignoring the new sending rules in 2025 risks seeing your marketing efforts collapse. Companies that don’t adapt face concrete consequences: lowered delivery and open rates, a weakened domain reputation, loss of qualified leads, and campaign blocks by providers.
Conversely, companies that take action now strengthen their inbox presence.
At LeadSider, we have supported many companies in this transition. Whether consulting firms, IT service companies, or e-commerce players, all had to adapt their email infrastructure. We helped them to:
Authenticate their domains
Review their email sequences
Integrate legal mentions and unsubscribe links
Set up deliverability monitoring tools
These technical and strategic adjustments allowed them to maintain strong deliverability while increasing their engagement rates.
In 2025, technical compliance and attention to user experience have become keys to effective emailing. The new rules are not meant to hinder marketing but to improve its quality.
Professionals who adapt enjoy a double benefit: enhanced deliverability and more effective campaigns.
📍 Want to run compliant and successful email campaigns?
At LeadSider, a leading agency in lead generation and digital prospecting, we support you from DNS record setup to the implementation of effective strategies to maximize your prospecting and deliverability.