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thenetworkery

Email deliverability test

Send an email to a one-off address and get a score: SPF, DKIM, DMARC, reverse DNS, blocklists and the headers Gmail and Yahoo require.

Get a test address

Send one message to it from the system you want to test – your mail client, newsletter tool, web shop or server – exactly as you send to customers. The report is ready a minute or so after it arrives.

What this tool checks

Record checkers tell you what your DNS says. This test looks at a real message: you send one email to a one-off address, and the report shows how a receiving server sees it. Send it from the system you want to test (your mail client, newsletter tool, web shop, CRM or server) exactly as you send to customers, because each of them can sign and route mail differently.

When the message arrives, the report covers:

  • The sending server: the last server that handed the message over, found in the Received headers, with its HELO name and whether it used TLS.
  • SPF: the full SPF evaluation (RFC 7208) for that server's IP and the envelope sender (Return-Path), following include: and redirect=, with the term that matched and the number of DNS lookups.
  • DKIM: every DKIM-Signature is verified against the key published in DNS (RSA and Ed25519), including the body hash, with the key size.
  • DMARC: the From domain's policy, and whether SPF or DKIM passed in alignment with it, which is what DMARC actually needs.
  • ARC: if the message went through a forwarder or list that seals it, the ARC chain is verified too.
  • Reverse DNS: the IP's PTR name, and whether that name points back to the IP (forward-confirmed reverse DNS).
  • Blocklists: the sending IPv4 address against the same public DNS blocklists as the blacklist check.
  • The message itself: Message-ID, Date, a single From address, plain-text and HTML parts, size, and for newsletters one-click unsubscribe (RFC 8058) covered by the DKIM signature.

Each problem takes points off a score of 10, and comes with the fix.

How to use it

  1. Click Get my test address. You get an address and a short code to put in the subject, valid for 30 minutes.
  2. Send one message to it. A normal message works best: a real newsletter, a password-reset email from your app, or a message from your mail client.
  3. Leave the page open. We check for mail every minute, and the report opens by itself.

Some systems refuse addresses with a + in them. In that case send to test@thenetworkery.com with the code from the page as the subject.

Privacy

The message is read once and deleted from our mailbox straight away. The report keeps only what it shows: the domains involved (not the full addresses), the sending server, the authentication results and the message's structure. The subject, the body and the attachments are never stored. The report has its own link, kept for 90 days, so you can share it with whoever runs your mail.

Common problems and fixes

SPF fails or soft-fails

The sending server's IP is not in the SPF record of the bounce domain. Add your mail service's include (or ip4:/ip6: for your own server) to the record, keeping a single record under 10 DNS lookups. The SPF record builder writes it for you.

DKIM is missing or signed by another domain

Most mail services sign with their own domain until you set up DKIM for yours. Turn it on in the service and publish the records it gives you. DKIM is the part of DMARC that survives forwarding, so it matters more than SPF.

DMARC fails although SPF passes

SPF passed for the service's bounce domain, not for your From domain. Either set up a custom bounce (return-path) domain under your domain, or rely on aligned DKIM: DMARC needs one of the two. Once everything passes, move your policy from p=none to p=reject, and use DMARC monitoring to see every sender while you do.

No reverse DNS, or it doesn't point back

Gmail rejects mail from IPs without reverse DNS. Ask whoever runs the IP (your hosting provider or ISP) to set a PTR record to the server's host name, and make sure that name has an A or AAAA record with the same IP.

Listed on a blocklist

Find the cause first: a compromised account, an open relay, a form that sends to any address, or malware. Then ask the list to remove the address. The blacklist check links to each list's removal page.

No one-click unsubscribe

Since 2024 Gmail and Yahoo require one-click unsubscribe from bulk senders. Add both headers and include them in the DKIM signature:

List-Unsubscribe: <https://example.com/unsubscribe/abc123>, <mailto:unsubscribe@example.com?subject=abc123>
List-Unsubscribe-Post: List-Unsubscribe=One-Click

FAQ

Does a score of 10 mean my email will reach the inbox?

It means the technical setup is right: authentication, alignment, reverse DNS, blocklists and the headers receivers require. Inbox placement also depends on your sending reputation, the content and how recipients engage with your mail, which no test can see from one message.

Why does the test need a real email instead of my domain name?

DNS records only say what should happen. A real message shows what does happen: which server actually sends it, which domain signs it, whether a gateway changes the body after signing, and which headers your software adds.

What happens to the email I send?

It is analysed once and deleted. Only the report is kept, without the subject, body or attachments, at a link that expires after 90 days.

Can I test more than once?

Yes. Each address takes one message; get a new address for each test. You can have three addresses waiting at a time.