Email Deliverability Test

Send one real email to a one-time address and see how it arrived: the sending server, SPF, DKIM, DMARC, content and SpamAssassin, scored out of 10.

Received by our own mail server (Cloudflare Email Routing as the backup) · SpamAssassin 4, local rules · Gmail's, Yahoo's and Outlook.com's sender rules · the full body is deleted after the analysis

Your test address

Getting your test address…

Send the email you want to test to this address, from the account and the service you really send it with. We never email you back.

Checking whether an address exists? Email Checker

Or paste a message

The source of an email you received (Show original in Gmail, View source in Outlook.com or Yahoo Mail), an .eml file, or just an email's text or HTML. Checked, then dropped: nothing is kept.

How to test your email deliverability

Send one real email to the address above, the way you always send it. The report builds as each part is checked.

1. Copy the test address. It takes one message for 2 hours. Nothing to sign up for, and we never email you back.

2. Send from the setup you really use: your mail app, your own server, or your email platform's real campaign to a segment that holds the address. A test reads the path the message took, so a message sent some other way tests something else.

3. Read the report. Our mail server records how your server connected (its address, its HELO name and the TLS it chose), then every check runs on the message itself: SPF, DKIM, DMARC, the format, the content, the unsubscribe headers and SpamAssassin. Most reports finish within a minute of the message arriving.

Fixed something? Re-check DNS reads SPF, DMARC, the DKIM keys and the reverse DNS again for the same message, without sending a new one (three times per report, a minute apart).

Your mail appyou press Send14:02:10
Your sending serveryour email serviceSendGrid · 198.51.100.24
Reverse DNS (PTR)HELO nameBlocklists
Our mail serverreceives it over TLSmailprobe.dnsrobot.net · TLSv1.3
the SMTP sessionTLS versionEHLO and pipeliningLine endings
the messageSPFDKIMDMARCARCFormatContentUnsubscribe
Your reportparts appear as they're checked14:02:24
SpamAssassinGmail · Yahoo · Outlook.com rulesScore

Backup: Cloudflare Email Routingroute1–3.mx.cloudflare.nettakes the mail if our server is down; it doesn't pass on the TLS details

What happens to your message

0 sarrives at our mail server11 sanalysis done: the body and attachments are deleted7 daysheaders, links and the preview deleted (or sooner: Delete report)

The example on this page: a newsletter sent through SendGrid. Each check lights where it happens: the sending server's identity, the SMTP session our server saw, the message's signatures and content, then SpamAssassin and the inbox providers' rules.

Email spam checker: what your score is made of

Ten points, minus deductions that each name their rule. A check we couldn't run never costs a point.

The table below is the scoring code itself, so the page can't say one thing while the score does another. The heavy deductions are the ones receivers act on: DMARC failing, nothing authenticating, a major blocklist, no reverse DNS.

Some rules count only for bulk mail. Gmail, Yahoo and Outlook.com ask bulk senders for both SPF and DKIM, DMARC and one-click unsubscribe; a one-to-one message gets those as recommendations, at 0 points.

Rows marked 0 points are warnings whose source we haven't confirmed yet: they show, and they cost nothing until a provider's own page backs them.

What is a good spam score?

Here, 10 means no deduction was found and 8 or more is in good shape. SpamAssassin's own scale runs the other way: its default spam threshold is 5.0, and its documentation calls that quite aggressive. A clean newsletter often scores about 1, which costs nothing here; above 2.0 half of SpamAssassin's points count, at most 3.

A made-up report

10 − 1.5 − 0.7 = 7.8

1Bulk mail without working one-click unsubscribe (RFC 8058: both headers, signed by DKIM)
2SpamAssassin 3.4

What we found	Points off	Part
Neither SPF passes nor any DKIM signature verifies	−3	SPF
DMARC fails: no aligned SPF or DKIM pass, and the From domain publishes a policy	−2.5	DMARC
The From header has no single domain DMARC can apply to	−2	DMARC
The From domain publishes no DMARC recordbulk mail only	−1	DMARC
SPF fail: the record says this server may not send	−1	SPF
SPF softfail or neutral	−0.5	SPF
No SPF record for the MAIL FROM (or HELO) domain	−1	SPF
SPF permerror: a broken record or more than 10 DNS lookups	−1	SPF
The message isn't DKIM-signedbulk mail only	−1	DKIM
DKIM-signed, but every signature fails (treated as unsigned)bulk mail only	−1	DKIM
A signature uses an RSA key under 1,024 bits	−1	DKIM
DKIM passes, but no passing signature matches the From domain	−0.5	DKIM
The sending address is on a major blocklist	−3	Sending server
The sending address is on a smaller blocklist	−1	Sending server
The sending address has no reverse DNS (PTR)	−2.5	Sending server
The PTR name doesn't resolve back to the sending address	−1.5	Sending server
HELO is not a fully qualified name	−0.5	Sending server
The server sent without TLS	−1.5	SMTP session
Bare LF or CR line endings in the message	0a warning, not counted in the score (−0.5 once a source is cited)	SMTP session
From is missing, repeated, unreadable, or lists several mailboxes without Sender	−2	Format
Date is missing or unreadable	−1	Format
Message-ID is missing or malformed	−1	Format
Date is more than a day from the time it arrived	0a warning, not counted in the score (−0.5 once a source is cited)	Format
A field that may appear once appears twice	−0.5	Format
Lines longer than 998 characters	−0.25	Format
Images with almost no text	0a warning, not counted in the score (−1 once a source is cited)	Content
HTML with no plain-text version	−0.5	Content
HTML over about 102 KB: Gmail may clip it	0a warning, not counted in the score (−0.5 once a source is cited)	Content
Links through URL shorteners	0a warning, not counted in the score (−1 once a source is cited)	Content
Links to a bare IP address	0a warning, not counted in the score (−1 once a source is cited)	Content
Links to a domain that imitates another	0a warning, not counted in the score (−2 once a source is cited)	Content
javascript:, data: or file: links	0a warning, not counted in the score (−2 once a source is cited)	Content
Link text shows one domain and the link goes to another	0a warning, not counted in the score (−0.5 once a source is cited)	Content
An attachment type Gmail blocks	0a warning, not counted in the score (−2 once a source is cited)	Content
Links to a host Cloudflare's security resolver blocks (malware or phishing)	0a warning, not counted in the score (−2 once a source is cited)	Content
Scripts, iframes, forms or embedded objects in the HTML	−1	Content
1Bulk mail without working one-click unsubscribe (RFC 8058: both headers, signed by DKIM)	−1.5	Unsubscribe
2SpamAssassin's points above 2.0	half the points over 2.0, at most 3	SpamAssassin
SpamAssassin's score reaches its spam threshold	−2	SpamAssassin
Not checked, or can't tell from one message	0	–

The table the score uses (version 2026-10-31.1): 10 minus every row that applies, never below 0. A part we couldn't check deducts nothing; bulk-mail rows cost points only on bulk mail; a row at 0 is a warning we show but don't count in the score.

Why emails land in spam

A receiving server decides in steps. One test message shows the first four; the last one only the receiver sees.

Who is connecting. The address your server sends from: is it on a blocklist, does it have a reverse DNS name that points back to it, did it use TLS? Gmail answers a missing reverse DNS with 4.7.23 or 5.7.25.

Who it claims to be. The HELO name and the envelope sender, checked with SPF. A failing SPF is a reason to defer or refuse, not just to file in spam.

Whether it's really from the From domain. DKIM signs the message, and DMARC checks that SPF or DKIM passes for the domain people see in From. Since 2024 Gmail, Yahoo and Outlook.com refuse or defer bulk mail that misses this.

What it says. Links, HTML, attachments and a content filter's score. This is where spam folders come from more often than refusals.

What your recipients do with it. Complaint rate, opens, replies and your sending history. No single message can show that: Google's Postmaster Tools shows Gmail's view, and Gmail asks for a spam rate below 0.3%.

What a receiving server checks, in order

Who is connectingBlocklistsReverse DNSTLSRefused with: 4.7.23 · 5.7.254.7.29
In this test
Who it claims to beHELOSPFRefused with: 4.7.27 · 5.7.27
In this test
Really from the From domainDKIMDMARCFormatRefused with: 4.7.30 · 4.7.32 · 4.7.40550 5.7.515
In this test
What it saysLinksHTMLSpamAssassin
In this test
What recipients doComplaintsEngagementHistoryGmail asks for a spam rate below 0.3% in Postmaster Tools.
Not in one message

Gmail, Yahoo and Outlook.com sender rules, and the codes they refuse with

When a provider defers or refuses a message, the reply code names the rule. Each one maps to a row of the report.

Gmail's codes start with 4 when the message is deferred (your server tries again) and 5 when it's refused. They reuse numbers that mean other things in the official list: read them with Gmail's own table, not a generic one.

Yahoo's FAQ says a bulk sender is one "sending a significant volume of mail. We will not specify a volume threshold." Gmail and Outlook.com draw the line at about 5,000 messages a day.

Reply codes Gmail and Outlook.com send for their sender rules, and the report row that shows each
Code	Provider	What it means	Report row
4.7.23 · 5.7.25	Gmail	The sending address has no reverse DNS (PTR), or its name doesn't resolve back to it	Sending server
4.7.27 · 5.7.27	Gmail	SPF didn't pass (bulk senders)	SPF
4.7.29 · 5.7.29	Gmail	The message wasn't sent over TLS	SMTP session
4.7.30 · 5.7.30	Gmail	DKIM didn't pass	DKIM
4.7.40 · 5.7.40	Gmail	No DMARC record or policy for the sending domain (4.7.31 in Gmail's sender FAQ)	DMARC
4.7.32 · 5.7.32	Gmail	The From domain isn't aligned with the SPF or DKIM domain	DMARC
550 5.7.515	Outlook.com	A high-volume sending domain doesn't meet Outlook.com's SPF, DKIM and DMARC requirement	DMARC

Who counts as a bulk sender

Gmail

About 5,000 messages or more to personal Gmail accounts within 24 hours, counted per primary domain. Once is enough: you stay a bulk sender.

Yahoo

"A significant volume of mail." Yahoo doesn't give a number.

Outlook.com

Domains sending more than 5,000 messages a day to Outlook.com, Hotmail and Live addresses.

One-click unsubscribe: the two headers bulk senders need

Gmail and Yahoo ask bulk mail for one-click unsubscribe (RFC 8058) and a visible unsubscribe link in the message.

One-click needs two headers. List-Unsubscribe holds exactly one HTTPS address (a mailto: may sit beside it), and List-Unsubscribe-Post says List-Unsubscribe=One-Click. A DKIM signature that passes must cover both, or a forwarder could change where the click goes.

The click is a POST, not a link someone opens: spam filters fetch every URL they find in the headers, and a plain link would unsubscribe the reader by itself. The same is why this test never fetches your message's links.

Yahoo accepts a mailto: link in List-Unsubscribe; Gmail wants the HTTPS one-click. Transactional mail, like receipts and password resets, doesn't need either.

The report also looks for an unsubscribe link in the body, in the words of twelve languages. Finding none is "can't tell", never a failure: the word may be one we don't know.

The headers of one-click unsubscribe (RFC 8058), and what each provider accepts

List-Unsubscribe: <https://example.com/unsubscribe/opaquepart>, <mailto:unsub@example.com>Exactly one HTTPS address; a mailto: may sit beside it
List-Unsubscribe-Post: List-Unsubscribe=One-ClickExactly this value
DKIM-Signature: v=1; a=rsa-sha256; d=example.com; s=s1; h=from:to:subject:date:list-unsubscribe:list-unsubscribe-post; …DKIM must sign both headers

What each one accepts
What each one accepts	Gmail	Yahoo
HTTPS, Post header, both signed	accepted	accepted
mailto: only	not one-click	accepted
HTTPS without the Post header	not one-click	not one-click

Check it in your own inbox

No placement test needed to see what one provider decided: send the same email to your own Gmail, Outlook.com or Yahoo address and paste what arrived.

Open the copy in your inbox and use Show original (Gmail) or View source (Outlook.com, Yahoo Mail), then paste it under the test address above, or save it as an .eml file and choose that. The card reads the results that provider wrote on that copy: SPF, DKIM and DMARC as it checked them, and Microsoft's spam and bulk levels where they are.

That is one provider's verdict on one copy. An inbox placement test sends to many seed mailboxes and reports where each copy landed that day; it is a different measurement, and we don't run one.

The same paste also runs the checks that read the message itself: format, content and links, the unsubscribe headers and SpamAssassin. A pasted email's text or HTML alone gets the content checks and SpamAssassin.

One copy in a Gmail inbox, and the results Gmail wrote on it

Received: from mta1.news.example.org (mta1.news.example.org. [192.0.2.25]) by mx.google.com with ESMTPS …
Authentication-Results: mx.google.com; dkim=pass header.i=@news.example.org header.s=s1; spf=pass smtp.mailfrom=bounce@news.example.org; dmarc=pass (p=NONE) header.from=news.example.org

spf=passSPF passed for the envelope sender's domain at the address that connected
dkim=passDKIM: a signature by news.example.org verified
dmarc=passDMARC passed: SPF and DKIM both match the From domain

The same email in an Outlook.com inbox, and what Microsoft adds

Authentication-Results: spf=pass (sender IP is 192.0.2.25) smtp.mailfrom=news.example.org; dkim=pass (signature was verified) header.d=news.example.org;dmarc=pass action=none header.from=news.example.org;compauth=pass reason=100
X-Forefront-Antispam-Report: CIP:192.0.2.25;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mta1.news.example.org;PTR:mta1.news.example.org;CAT:NONE;SFS:;DIR:INB;
X-Microsoft-Antispam: BCL:4;
Received: from mta1.news.example.org (192.0.2.25) by DB5PEPF00014B8F.mail.protection.outlook.com …

compauth=passMicrosoft's own check of the From domain: reason 100, SPF or DKIM passed with aligned domains
BCL:4Bulk complaint level 4, a mixed number of complaints: below Microsoft's thresholds (7 by default, 5 at its strictest)
SCL:1Spam confidence level 1: from 0 to 4 it doesn't decide the verdict, it's one input to filtering

Made-up copies (example.org, a documentation address). The paste card shows these results for any copy you paste, as the provider wrote them.

Email tester or email checker: which one do you need?

An email deliverability checker reads your sending. An email checker reads an address. Here is which tool answers which question.

Tool	You give it	It answers
Email deliverability test	One real email you send	How it arrived: server, SPF, DKIM, DMARC, content, SpamAssassin and the providers' rules, scored out of 10
Email Checker	An email address	Whether its mailbox exists, by asking its mail server and stopping before anything is sent
Email Header Analyzer	The header of an email you received	Its path, and what the receiving provider decided about SPF, DKIM and DMARC
SMTP Test	A mail server	Its greeting, TLS, certificate and whether it relays for strangers
SPF, DKIM and DMARC checkers	A domain	The records it publishes and what is wrong with them
Inbox placement test	One send to many seed mailboxes	Which folder it landed in at each provider, that day. We don't run seed mailboxes, so we don't offer one

What we keep, and for how long

The address is random and opens nothing else. The full body of your message is deleted the moment the analysis ends.

The report keeps the headers, the links, a 140-character preview and what each check found; the full body and attachments are deleted. It stays 7 days, opened only by its link, and Delete report removes it at once.

To score it, the raw message goes once to SpamAssassin on our own mail server and is scored in memory. Nothing you send is used for anything else, and we never email you or the sender.

What happens to a test message

0Your test address is made: random, one message
≤ 2 hYour email arrives at our mail server
~1 minChecked; the full body is deleted
7 daysThe report (headers and findings) is deleted

Delete report removes it at any time.

Frequently asked questions

How do I send a test email?

Copy the test address at the top of this page and send your email to it the way you normally send: from your mail app, your own server or your email platform. For a newsletter, add the address to a small segment and send the real campaign. The report starts as soon as the message arrives.

Is this email deliverability test free?

Yes. There is no sign-up and no daily cap, and we never email you back. Each test address takes one message for 2 hours, so run a new test for each email you want to check. Only very frequent requests from one network are slowed for a minute.