Check Email Spam Score Before Sending with mail-tester.com

Before sending an important email campaign, always check your spam score. A tool like mail-tester.com tells you exactly how likely your emails are to be caught by spam filters — and which specific issues need to be fixed before sending to real recipients.

What Is a Spam Score?

A spam score is a number that email filters at recipients (Gmail, Outlook, etc.) use to decide whether an email goes to Inbox or Spam. Higher scores (passed checks) mean better inbox delivery. Key factors include SPF, DKIM, DMARC configuration, email content, IP reputation, and email headers.

How to Use mail-tester.com

1. Go to mail-tester.com
2. You'll receive a temporary test address like [email protected]
3. Send the email you want to test to that address — send it from your actual hosting/mail server, not a personal Gmail
4. Return to the website and click "Then check your score"
5. Review your score and the list of issues to fix

Understanding Email Headers and Their Effect on Spam Score

Beyond SPF, DKIM, and DMARC, spam filters also analyse a range of additional email header fields: Return-Path, Message-ID, the Received chain, and X-Mailer, which reveals what software sent the message.

Well-formed headers look like this:

• Return-Path should match the sending domain, not a random IP or a third-party domain.
• Message-ID should follow the pattern <[email protected]> — never @localhost.
• The Received chain should contain no blacklisted IPs along its path.
• X-Mailer should not identify a bulk-mailing tool that filters already flag.
• The Date header must reflect a realistic timezone, not a server default gone wrong.

When you run a test through mail-tester.com, the header analysis section highlights any anomalies so you can fix the exact field that is causing the problem, rather than guessing.

IP Reputation and Domain Reputation Explained

Even with perfect SPF, DKIM, and DMARC, a sending IP with a poor reputation — one previously used to send spam — will drag your email into spam folders. Gmail and Outlook evaluate two distinct dimensions:

• IP Reputation — the history of the IP address used to send mail. Check it at mxtoolbox.com/blacklists and Google Postmaster Tools.
• Domain Reputation — the track record of your From domain: complaint rate, bounce rate, and unsubscribe rate. Lower is better.

For a new IP, warming up gradually — rather than blasting thousands of emails on day one — signals normal behaviour to providers. A typical warm-up schedule:

Comparing Spam Score Testing Tools

mail-tester.com is a great starting point, but combining it with other tools gives a more complete picture:

For most small businesses using AsiaGB Email Hosting, mail-tester.com combined with MXToolbox provides everything needed. Run a test before every significant campaign.

Common Issues and How to Fix Them

1. SPF Failing

Your SPF record must include the IP addresses authorized to send email for your domain. Example SPF for AsiaGB Hosting:

v=spf1 +a +mx +ip4:YOUR.SERVER.IP ~all

2. DKIM Not Configured

In DirectAdmin → Email Manager → DKIM Keys, generate a DKIM key pair and add the resulting DNS TXT record to your domain.

3. DMARC Missing

Add a TXT record named _dmarc.yourdomain.com with value:

v=DMARC1; p=none; rua=mailto:[email protected]

4. Blacklisted IP

If your server IP is on a blacklist, check it at mxtoolbox.com/blacklists and submit a delisting request to each blacklist that lists it.

5. Spammy Content

Avoid words like "FREE!!!", "100% discount", "CLICK HERE NOW" in subject lines, and avoid emails that are 100% images with no text content.

Getting a Perfect 10/10 Score

• Set up SPF, DKIM, and DMARC completely
• Use a From address matching your actual domain — not Gmail or Hotmail
• Include an Unsubscribe link (especially for newsletters)
• Maintain a text-to-HTML ratio of approximately 60:40
• Don't include URLs that are blacklisted

Long-Term List Hygiene for Sustained Deliverability

A good spam score is not a one-time achievement — it requires ongoing attention to your email list. Follow these practices to protect your sender reputation over time:

• Remove hard bounces immediately — addresses that permanently reject mail should be deleted after the first bounce. Sending to them again hurts your reputation.
• Handle soft bounces carefully — if an address soft-bounces three or more times in a row, pause sending to it until the issue is resolved.
• Use double opt-in — require subscribers to confirm their address before being added to your list. This eliminates typos and dramatically reduces complaint rates.
• Run re-engagement campaigns — subscribers who have not opened an email in six months should receive a "Do you still want to hear from us?" message. Remove those who do not respond.
• Monitor complaint rate in Postmaster Tools — Gmail recommends keeping complaint rates below 0.1%. Rates above 0.3% result in throttling or blocking.
• Send at optimal times — identify peak open-rate windows for your audience and schedule sends accordingly; consistency signals normal sending behaviour.

High engagement — opens, clicks, and replies — directly improves your domain reputation, making future emails more likely to reach the inbox. Quality content and a clean list create a self-reinforcing cycle of better deliverability.