Email Delivery Checker: See What a Receiving Server Records
A new billing platform, CRM, or marketing tool can send email that isn't accounted for in a domain's SPF, DKIM, and DMARC records, and a DNS lookup won't catch that.
Sendmarc's email delivery checker tests a real message instead of a published record. Send one email to a generated address and see the authentication result, alignment, spam score, and sending IP a receiving server recorded for it.
Preparing your test inbox
Send a test email to the address below to get started.
What Is an Email Delivery Checker?
An email delivery checker tests one real message against a receiving server's own record of it, rather than looking up a domain's published DNS records. It reports SPF, DKIM, and DMARC results, alignment, spam score, and sending IP.
IT administrators use it to confirm a new sending system authenticates correctly. Security teams use it to investigate why legitimate email is landing in Spam. Email marketers use it to verify a campaign tool aligns with the sending domain before a broad send goes out.
Why Delivery Testing Matters
A domain's core records can be correctly configured for the senders they were built around. A new system added later, like a billing platform, CRM, or marketing tool, can still go live without ever being added to the SPF record or set up to sign with DKIM.
A DNS lookup won't surface that gap. It shows what the domain's records permit, not what a specific system actually sends or how a receiving server treats that email.
Spam score and sending IP reputation aren't part of a records lookup at all. Both depend on the message and the sending infrastructure, not the domain's published policy, so testing a live message is the only way to see them.
DNS record
This message
What Sendmarc's Email Delivery Checker Shows You
Send one message and get a structured report across five areas.
- SPF. Whether the sending IP is authorized to send for the domain. A fail here is a common reason email never reaches an inbox.
- DKIM. Whether the message's cryptographic signature still matches on arrival. A fail means the message was altered in transit or was never signed.
- DMARC alignment. Whether the "From" header domain aligns with the SPF or DKIM domain. Receiving servers use this result to decide whether to deliver, quarantine, or reject the message.
- Spam score. How the test inbox scored the message, and which rules contributed to that score. This runs independently of authentication and still affects placement.
- Sending IP. The IP address that delivered the message, its reputation score, and any blocklists it appears on.
How to Use Sendmarc's Email Delivery Checker
- Copy the test address. Each session uses a unique inbox.
- Send a message. Send from the exact system you want to test.
- Wait for the result. The report replaces the waiting state once the test inbox receives and parses the message.
- Read the report. Review the verdict first, then the tables: SPF, DKIM, DMARC, alignment, spam score, and sending IP.
Run a new check whenever a sending system changes, or whenever a specific system's authentication needs to be confirmed rather than assumed.
Email Delivery Checker FAQs
What is an email delivery checker?
An email delivery checker tests one real message against a receiving server's own record of it, rather than looking up a domain's published DNS records. It reports SPF, DKIM, and DMARC results, alignment, spam score, and sending IP.
How is this different from an SPF, DKIM, or DMARC record checker?
A record checker looks up the published DNS. This tool shows what happened to a message you actually sent. Use both: DNS for the policy on the domain; this checker for the path that sent the email.
How long should I wait for results?
Results appear after the test inbox receives and parses the message, typically within several seconds of arrival. If nothing shows, confirm you sent to the generated address for this session and that the message was under 1 megabyte.
What does a fail or alignment mismatch mean?
A fail means the receiving server didn't authenticate that check on this message. Alignment mismatch means the "From" domain didn't match the SPF or DKIM domain, which is why DMARC can fail even when SPF or DKIM individually pass.
Can I reuse the address or send more than one email?
Each session is built around one inbound message. Start a new check for another test. Duplicate email to an already-received session is ignored.
Will this tell me if Gmail or Outlook will put the message in the inbox?
No. This checker reports authentication, spam scoring on the test inbox, and IP reputation signals. It doesn't predict Gmail or Outlook placement.
When should I use the email header analyzer instead?
Use this checker when you can send a live test. Use the email header analyzer when you already have a header from a received message and need to parse Authentication-Results without sending again.