Domain authentication proves to inbox providers like Gmail and Yahoo that you have permission to send emails from your domain. It involves adding DNS records that verify your identity as a legitimate sender.
When you'll need this
Read this article if you're setting up SendX for the first time, your emails are landing in spam folders, you want to protect your brand from spoofing, or you need to meet Gmail and Yahoo's sender requirements.
Why domain authentication matters
When you send an email campaign, the recipient's inbox provider asks a simple question: "Is this sender who they claim to be?" Without authentication, there's no way to answer that confidently. Your emails may land in spam, get blocked entirely, or be flagged as phishing attempts.
Authentication creates a verifiable link between your domain (like yourbusiness.com) and the emails you send through SendX. It tells inbox providers, "Yes, this business authorized these emails."
Three reasons to authenticate your domain
1. Deliverability
Authenticated emails are far more likely to reach the inbox. Gmail, Yahoo, Microsoft, and other providers use authentication as a key signal when deciding whether to deliver your email, send it to spam, or reject it outright.
2. Brand protection
Without authentication, anyone can send emails that appear to come from your domain. This is called spoofing, and it's a common phishing tactic. Proper authentication helps prevent bad actors from impersonating your brand.
3. Compliance with inbox provider requirements
As of February 2024, Gmail and Yahoo require bulk senders (those sending more than 5,000 emails per day) to have proper email authentication in place. Senders who don't comply may see their emails rejected or filtered to spam.
How domain authentication works
Domain authentication uses DNS records, which are public entries associated with your domain. Think of DNS records like a phone book for the internet. When you add authentication records, you're publishing information that inbox providers can look up to verify your emails.
SendX uses two main authentication methods:
DKIM (DomainKeys Identified Mail)
DKIM adds a digital signature to your emails. When an inbox provider receives your email, it checks this signature against a public key published in your DNS records. If the signature matches, the provider knows the email hasn't been tampered with and truly came from an authorized sender.
DMARC (Domain-based Message Authentication, Reporting & Conformance)
DMARC tells inbox providers what to do when an email fails authentication checks. Should they deliver it anyway? Send it to spam? Reject it completely? DMARC also enables reporting, so you can see who is sending email using your domain.
What about SPF?
SPF (Sender Policy Framework) is another common authentication method. When you send emails through SendX, SPF authentication is handled automatically on our end. You don't need to add a separate SPF record for SendX because emails are sent through our infrastructure, which is already authorized.
Your DKIM and DMARC records work together with SendX's SPF to provide complete authentication coverage.
What you'll need
To authenticate your domain in SendX, you'll need:
Access to your domain's DNS settings (usually through your domain registrar or hosting provider, such as GoDaddy, Cloudflare, or Namecheap)
A few minutes to copy and paste records from SendX into your DNS
Patience for DNS propagation, which can take up to 48 hours (though it's often much faster)
If you don't manage your domain's DNS directly, you may need to contact your IT team or the person who does. SendX includes a "Send Instructions" feature that lets you email the required DNS records to someone else.
Getting started
Ready to authenticate your domain? See our step-by-step guide: How to Authenticate a Domain in SendX
If you'd like to understand DMARC in more depth before getting started, read The Basics of DMARC.
Common questions
Do I need to authenticate my domain if I only send a few emails?
Yes. While Gmail and Yahoo's strictest requirements apply to bulk senders (5,000+ emails/day), authentication improves deliverability for all senders. Even small senders benefit from better inbox placement and brand protection.
Can I send emails without authenticating my domain?
You can, but your deliverability will suffer. Unauthenticated emails are more likely to land in spam or be blocked entirely, especially by major providers like Gmail and Yahoo.
How long does authentication take to work?
Once you add the DNS records, they typically propagate within a few hours, though it can take up to 48 hours in some cases. You can use the "Recheck Status" option in SendX to verify when your records are live.
What if I use multiple email tools besides SendX?
Each tool may require its own DKIM record. DMARC and SPF records need to account for all your sending sources. If you use multiple email services, you may need to coordinate your DNS records carefully. Contact our support team if you need help.
I don't have access to my DNS settings. What should I do?
Use SendX's "Send Instructions" feature to email the required DNS records to your IT team, web developer, or whoever manages your domain. They can add the records on your behalf.