Free Email Spam Checker

01 · Definition

What is email spam checker?

An email spam checker is a deliverability tool that sends a real test message through public spam filters and authentication checks, then scores the result so you can see exactly why an inbox would accept or reject it. Unlike a static record audit, the spam checker reads the actual headers and body of a delivered message and grades nine signal groups: SPF, DKIM, ARC, DMARC, sending domain, sending IP, message body, subject line, and links.

The tool above issues you a one-time @spotzee.marketing test address. Send any campaign or cold-email draft to that address from your real sending infrastructure, and the spam checker scores 400 points worth of authentication, reputation and content checks. Use it as a free email spam checker before a campaign send, an inbox placement test for a new sending domain, or an evidence trail for the deliverability conversation with your ESP. Read the in-depth email spam checker guide for what every score signals and the order to fix issues in.

02 · Process

How it works

1. 1Generate a test inbox.Click the button to claim a unique @spotzee.marketing address. Spotzee receives mail at that address through a Cloudflare Email Routing rule and stores the captured payload, headers and all.
2. 2Send your draft from real infrastructure.Send any campaign, transactional message or cold-email draft from your production ESP, SMTP relay or mail client. The tool checks what receivers actually see, so the send must come from the same setup you use in production.
3. 3Wait for the spam checker to capture and parse the message.The tool polls every few seconds. As soon as the message lands, it parses the MIME tree, headers and HTML body, then runs nine analysis modules in parallel.
4. 4Score authentication, reputation and content.SPF, DKIM and DMARC alignment check the records and the actual Authentication-Results header. Domain age, blacklist status and MX presence score the sending domain. The IP module checks the sender IP against blacklists, reverse-DNS and host-record alignment. Body and subject-line modules grade spammy words, hidden content, broken links, image-only payloads and missing list-unsubscribe headers.
5. 5Return a single percentage with a per-bucket breakdown.The final score is obtainedScore / 400 rounded to a percentage, with each bucket exposed as a separate score so you can fix the heaviest contributors first.

03 · Risk

Why it matters

A campaign that lands in spam costs everything it would have earned plus the sender-reputation hit that follows. Mailbox providers downgrade unauthenticated mail before any human ever sees it. Spam-trigger language, broken DKIM signatures and IPs that appear on a blacklist all push placement from inbox to junk in a single send. The cheapest way to find these issues is to test before the campaign goes out, not after.

For regulated firms the cost is steeper. An unauthenticated message is an audit-trail problem, not just a deliverability problem. Mailbox providers junk-fold the message, the customer never sees it, and the firm has no record of what was actually delivered to whom. A pre-send spam check gives compliance, marketing and oncall the same evidence in the same place: what the receiver sees, scored against the things receivers grade you on.

04 · Use cases

Common ways to use this tool

• Pre-campaign deliverability audit. Before sending a marketing email or financial promotion, route a copy through the spam checker and confirm SPF, DKIM and DMARC all pass and the score is at or above 80%.
• Cold email and outbound prospecting. Sales teams running cold outbound from a fresh domain need to know whether the first email gets read. The cold email spam checker flow surfaces every reason a receiver might filter the message, from a too-short body to a missing list-unsubscribe header.
• New sending domain or IP warm-up. When you cut over to a new domain or dedicated IP, send a probe through the spam checker first. Domain age, MX presence, IP blacklist status and reverse-DNS alignment all score in one pass, so you know the new infrastructure is ready before live traffic hits it.
• Vendor template review. When an ESP, agency or in-house team hands you a new template, send it through the spam checker before approval. The body-level checks flag image-only emails, hidden content, broken links and oversized URLs that templates often introduce.
• Deliverability incident triage. Inbox placement just dropped on one ISP. Send a probe, compare the score against the last green capture, and check which bucket regressed. SPF lookup count, DKIM selector mismatches and DMARC alignment are the three causes that show up most often.

05 · Interpretation

What to check in the result

Read the result in priority order — the cheapest fixes give the biggest score lifts:

• Final score under 80%. Anything below 80% has at least one structural issue worth fixing this week. Above 90% is the bar for production sending domains; 95%+ for compliance-sensitive senders.
• SPF, DKIM, DMARC failures. These three buckets dominate the score. An SPF over the 10-DNS-lookup cap, a DKIM signature with a missing selector, or a DMARC policy of p=none will all knock 30–50 points off the total in one move.
• Domain or sending-IP blacklist hits. A domain or IP listed on more than one blacklist is the single fastest way to land in spam. Resolve listings before the next campaign send, not after.
• Spammy subject and body words. The subject-line module flags shouty punctuation, common spam triggers and a low subject-line score. The body module flags spammy phrases, hidden content (display:none, opacity:0) and image-only payloads with no readable text.
• Missing List-Unsubscribe header. RFC 8058 one-click unsubscribe is now a hard requirement for bulk senders at Gmail and Yahoo. The body module checks both the header and an in-body unsubscribe link.
• Broken, oversized or shortened links. The links module scores broken HTTP fetches, URLs over 70 characters, blacklisted domains in any link and any use of a known URL shortener. Each is a small subtraction; together they add up.