How often should I run an email deliverability test?

At a minimum, run it whenever you add a new sending source (a new ESP, CRM, or transactional provider), whenever you change your DNS configuration, and any time you notice an unexplained drop in open or click rates. For active senders, a monthly check is a reasonable habit.

Does passing this test guarantee my emails land in the inbox?

No, and any tool claiming otherwise is overselling. Authentication is one major factor in deliverability. List quality, engagement history, sending volume patterns, content, and domain age all play roles too. But failing authentication is a guaranteed deliverability problem. Passing it removes a significant obstacle.

What's the difference between this test and a seed list test?

A seed list test sends a real email to a list of test addresses at major mailbox providers and reports on inbox vs. spam placement. This test checks your DNS authentication records, no email needs to be sent. They answer different questions. A seed list test tells you where your email landed; this test tells you whether your authentication configuration is correct.

My DKIM check failed but my ESP says DKIM is set up. What's happening?

The most common reason is a mismatch between the DKIM selector being checked and the one your ESP is actually signing with. Ask your ESP which selector they use (it's often something like google._domainkey or a custom string), and confirm that exact TXT record exists in your DNS. Also verify the record has fully propagated, use a DNS lookup tool to confirm the record resolves correctly.

Can I test deliverability for a domain I don't own?

The tool queries publicly available DNS records, so technically any domain can be checked. It's genuinely useful for competitive research, seeing how other senders in your industry have their authentication configured. That said, the results are only actionable for domains you control.

Why do some tools show a different result than yours?

Different tools check different things and use different scoring methods. One tool might only check whether a record exists; another might validate the syntax more strictly. If you get conflicting results, the most useful thing is to check what specifically each tool is testing and compare at that level.

Free Email Deliverability Test - Check SPF, DKIM & DMARC

Most deliverability problems aren’t caused by what you send, they’re caused by how your domain is configured. A sender with clean lists and great content can still end up in spam if their SPF record is broken, their DKIM signature isn’t set up, or their DMARC policy is missing. The problem is invisible until something goes wrong.

This free email deliverability test checks your authentication setup from the outside: the same perspective a receiving mail server has when your email arrives. Enter a sending address and see whether your SPF, DKIM, and DMARC records are configured correctly and what’s failing if they’re not.

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What this email deliverability test checks

Most deliverability testing tools either require you to send a test email to a seed address or focus only on content scoring. This one focuses on your domain’s authentication layer, the DNS configuration that mailbox providers check before they even look at your content.

Here’s what the test evaluates:

SPF (Sender Policy Framework): Whether your domain has a valid SPF record, whether it’s within the 10-lookup limit, and whether the syntax is correct. An SPF record that exists but is malformed is almost as bad as not having one.

DKIM (DomainKeys Identified Mail): Whether a valid DKIM public key is published for your domain’s signing selector. Note that this check confirms the DNS record exists, actual signature validation requires a live email to be sent and inspected.

DMARC: Whether a DMARC record exists, what policy it’s set to, and whether reporting addresses are configured. A p=none policy with no reporting addresses is functionally useless, you’re getting no data and enforcing nothing.

The combined score gives you a quick read on your authentication health. A passing score doesn’t guarantee inbox placement (content, sending reputation, and list hygiene all factor in), but failing authentication is one of the clearest reasons email gets blocked or filtered, and it’s fixable.

Why email deliverability testing matters more than it used to

Getting email delivered used to be relatively forgiving. Mailbox providers were lenient, authentication was loosely enforced, and even misconfigured domains could often squeak through.

That window has closed.

In early 2024, Google and Yahoo updated their requirements for bulk senders: SPF or DKIM is required, DMARC is required (at minimum p=none), and one-click unsubscribe is mandatory for certain senders. Microsoft followed with similar signals for Outlook. These aren’t spam filter preferences; they’re published requirements with real enforcement behind them.

We’ve seen companies discover they had a broken SPF record only after their open rates dropped 40% in a week. The fix took 15 minutes. The recovery took months. Testing your authentication setup regularly isn’t paranoia, it’s maintenance.

Understanding your results

SPF pass: Your domain has a valid SPF record, and the sending IP is authorized. This is the baseline.

SPF softfail or fail: Either your SPF record doesn’t include the sending source, or the record has syntax errors. Check that every platform sending email on your behalf has an include: entry in your SPF record. Use our free SPF record generator to rebuild the record correctly.

DKIM pass: A valid DKIM public key is published for the selector being checked. If you’re using an ESP, confirm you’ve completed the DKIM setup in both their platform and your DNS, it typically involves adding a CNAME or TXT record at a specific subdomain.

DKIM not found: The DKIM record for the checked selector doesn’t exist in DNS. If you recently set up DKIM, allow up to 48 hours for propagation. If it’s been longer, check that the record was added to the correct subdomain.

DMARC pass: A valid DMARC record exists. Check the policy level; if it’s p=none, your authentication is technically in place but not enforcing anything. A p=reject or p=quarantine policy provides real protection.

DMARC missing: No DMARC record exists at _dmarc.yourdomain.com. This is one of the most common gaps we see. Use our free DMARC record generator to create one.

How email authentication affects deliverability

SPF, DKIM, and DMARC are sometimes described as separate checks, but mailbox providers evaluate them as a system. Here’s roughly how that works in practice:

When an email arrives, the receiving server checks SPF first: is this IP authorized to send from this domain? Then it verifies the DKIM signature: was this message signed by the domain it claims to be from? Then it checks DMARC: does the domain in the From: header align with the domain that passed SPF or DKIM? And finally, what does the DMARC policy say to do with failures?

An email that passes all three checks is treated very differently from one that fails even one. Consistent failures, or a missing DMARC record, signal to mailbox providers that a domain isn’t properly managed. Over time, that affects your sender reputation, which affects deliverability even for emails that would otherwise be fine.

The good news: authentication is entirely in your control. It’s DNS configuration. It doesn’t require a new platform, a new process, or budget. It just requires knowing what’s wrong.

Authentication is the foundation. Once it’s solid, the rest of deliverability work, list hygiene, engagement metrics, content quality, sits on top of it properly. If you found gaps in your SPF or DMARC setup, our free SPF record generator and free DMARC record generator will help you fix them.

And if you want to check your content alongside your authentication, whether your subject line or body copy is triggering spam filters, our free email spam checker covers that side of the picture.

For Alterable users: every personalized campaign you send is only as good as its chance of being delivered. Getting authentication right is the first thing we’d recommend checking.

Free Email Deliverability Test

Enter Your Email Address

Deliverability Report

What this email deliverability test checks

Why email deliverability testing matters more than it used to

Understanding your results

How email authentication affects deliverability

Frequently asked questions

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