How to test email deliverability.
The only reliable way to test email deliverability is to send real emails to inboxes you can check, and record where each one lands. Delivery reports cannot tell you this: an email filed to spam still counts as delivered.
Everything else, authentication checks, blacklist lookups, Postmaster Tools, explains why you land where you land. Placement testing is the measurement itself, and you can get one run for free below.
Every way to test deliverability, ranked by what it proves.
One method measures placement. The other four diagnose it. A serious test setup uses all five, in this order.
Seed-list placement test: the ground truth
Send your actual email to real, monitored inboxes at each provider and record the folder it lands in. This is the only method that measures placement directly. Run it before the campaign: seed inboxes that open, read, and mark the message as important teach filters the content is trusted before your real list ever sees it.
Google Postmaster Tools: the Gmail scoreboard
Free from Google, and worth setting up for any domain that mails Gmail at volume. It shows domain reputation, spam-complaint rate, and authentication results as Gmail sees them. What it will not show: where any individual message landed, or anything about Outlook, Yahoo, and the rest.
Authentication check: the entry ticket
SPF, DKIM, and DMARC are pass-fail requirements at every major provider. A broken record does not reduce your deliverability, it caps it. Check all three any time you change DNS, sending tools, or domains, because a silent DKIM failure can zero out placement overnight.
Blacklist check: the tripwire
A listing on Spamhaus or a similar blacklist suppresses delivery everywhere that list is consulted, which is most of the internet. Blacklist checks take seconds and rule out the most catastrophic single cause of sudden deliverability collapse.
Content analysis: the tiebreaker
Spam-signal scoring of the email itself: link patterns, formatting, trigger phrasing, tracking pixels. Content is rarely the whole story, reputation usually outweighs it, but on a borderline sender it is the difference between inbox and spam.
Test before the campaign, not after it fails.
Most teams discover deliverability problems from a collapsed reply rate. By then the damage is already priced in.
Before beats after
A placement test before the send costs you nothing. Discovering spam placement after the send costs you the campaign, plus the engagement damage of a thousand unopened emails.
Seeds go in early
Seed lists are typically emailed before the real campaign goes out. The monitored inboxes engage with the message so filters classify the content as trusted, which lifts placement for the real recipients that follow.
Mid-campaign, seeds are the alarm
Kept in the send, seed inboxes flag a placement slide while the campaign is running, and anything that hits spam gets pulled back out in real time, not discovered in next week's reply-rate report.
One test is a snapshot
Reputation drifts with every send, so placement testing works best as a routine, not a rescue. The teams with the best numbers test every meaningful campaign.
Run the diagnostic checks right now.
Three of the five checks take under a minute each with our free tools. No signup, no email required.
Then run the measurement itself: request a Free Deliverability Test below and the MailStrike team will send your email through real monitored inboxes and report the verdict provider by provider.
See where your emails actually land.
Fill in the form and MailStrike runs a placement test on your email: scored for spam signals, then sent and reported provider by provider.
- Content analysis: your email scored for the spam signals filters check
- Placement test: inbox, promotions, or spam, per provider
- Every major provider, results in minutes
No card required.
Deliverability testing questions.
How do I test my email deliverability?
Send real emails to a controlled set of inboxes you can check, and record where each one lands: inbox, spam, or a Gmail tab. That is a placement test, and it is the only method that measures the thing you actually care about. Supporting checks, authentication records, blacklist status, and Postmaster Tools reputation, tell you why placement is what it is.
How can I check if my emails are going to spam?
You cannot see it from your own sending dashboard: mail filed to spam still counts as delivered. Send to seed inboxes at each major provider and look. A placement test across Gmail and Outlook inboxes shows the folder-by-folder verdict within minutes of the send.
What is a seed list test?
A seed list is a set of real, monitored inboxes spread across providers. You add them to a send, typically before the real campaign goes out, and each one reports where the message landed. Because the inboxes are monitored, mail that hits spam can also be engaged with and pulled back out, which teaches filters the message is wanted.
Is Google Postmaster Tools enough to measure deliverability?
No, but it is a valuable free supplement. Postmaster Tools shows your domain reputation, spam-complaint rate, and authentication status as Gmail sees them, but it never tells you where individual messages were filed, and it covers only Gmail. Pair it with placement testing for the full picture.
How often should I test deliverability?
Before every meaningful campaign, and continuously during high-volume sequences. Reputation moves week to week, so a test from last month says little about tomorrow's send. Teams running regular outreach treat placement testing like a pre-flight check rather than a one-off audit.