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Deliverability testing: send one real email and inspect every signal.

Learn how WillItInbox test inboxes work, what the report checks, and how to turn findings into deliverability fixes.

Run a test Sample report

0-100

weighted score

score categories

24h

short raw email retention

How the test flow works

WillItInbox generates a unique test address. You send a message to that address from the exact app, ESP, domain, and template you want to evaluate. The report analyzes what a receiver can see.

Generate a unique inbox for a single test.
Send the same message your customers would receive.
Review authentication, DNS, headers, content, links, score, and prioritized fixes.

What the report checks

The score is intentionally weighted toward signals mailbox providers care about before content reputation can help you.

Authentication

SPF, DKIM, DMARC, alignment, policy strength, selector lookup, and BIMI signals.

Infrastructure

PTR, forward-confirmed rDNS, HELO, MX, DNSBLs, dynamic IP signals, and TLS.

Message quality

Required headers, SpamAssassin signals, MIME shape, unsubscribe, address, attachments, and links.

When to re-test

Run a fresh test after meaningful DNS, ESP, template, domain, or sending infrastructure changes. Do not treat one old report as proof that future campaigns are safe.

After SPF, DKIM, or DMARC changes propagate.
Before a large newsletter or lifecycle campaign.
After changing ESPs, tracking domains, templates, or link destinations.

FAQ

Does the deliverability test guarantee inbox placement?

No. It shows technical deliverability signals and likely risk. Inbox placement still depends on reputation, engagement, recipient history, and provider behavior.

Should transactional and marketing messages be tested separately?

Yes. They often use different templates, headers, links, subdomains, and sending systems.