Domain authentication overview

Domain authentication tells inbox providers (Gmail, Outlook, Yahoo, etc.) that rasa.io is allowed to send email on behalf of your domain. It's one of the most important things you can do for newsletter deliverability.

Why it matters

When you send email through rasa.io without authenticating your domain, inboxes see "via sendgrid.net" next to your sender name. That looks generic and reduces trust.

When you authenticate your domain:

• Emails show as coming from your domain (e.g., "newsletter@yourbrand.com") with no "via" tag
• Inbox providers trust your emails more
• Deliverability improves — fewer emails land in spam
• Your sender reputation builds over time

What domain authentication does technically

Authentication uses DNS records to prove ownership. When rasa.io sends an email on your behalf, the receiving inbox provider checks DNS to confirm rasa.io is authorized.

The records handle:

• SPF (Sender Policy Framework) — proves authorized senders
• DKIM (DomainKeys Identified Mail) — signs each email with a cryptographic signature
• DMARC (Domain-based Message Authentication, Reporting & Conformance) — policy that ties it all together

rasa.io provides the specific DNS records you need to add for SPF and DKIM. DMARC is optional but recommended.

Use a subdomain

We recommend setting up authentication on a subdomain like:

• newsletter.yourbrand.com
• email.yourbrand.com
• news.yourbrand.com

Using a subdomain has advantages:

• Keeps your main domain's reputation separate from email sending
• Easier to manage DNS records
• If you change email providers later, you don't affect your main domain

What you'll need

• Access to your domain's DNS settings (often via your hosting provider, web team, or IT department)
• The DNS records rasa.io generates for you
• About 30 minutes for the actual setup (plus up to 48 hours for DNS propagation)

Before you begin

• Check who manages your DNS — often it's your IT team, web developer, or whoever set up your website
• Have a sender address in mind — what email will you send from? newsletter@yourbrand.com is common
• Confirm the subdomain is OK to use — it shouldn't conflict with anything else

Sending from free email providers (Gmail, Yahoo, etc.)

You cannot authenticate addresses like yourname@gmail.com. Free email providers don't allow third-party sending on their behalf.

If you currently use a free email address for your "from" address, you'll need to switch to a domain you control before authentication will work.

What's next

• How to authenticate your domain — step-by-step authentication walkthrough
• Display Issues: Why Emails Appear Differently Across Platforms