The Inbox Placement Test Center is a tool designed to help you determine where your emails land when sent to major ISPs like Gmail, Yahoo, Hotmail, and Apple Mail. Instead of waiting for real-world campaign performance data, this tool lets you proactively check whether your emails are reaching the inbox, spam folder, or are being blocked entirely.
We provide multiple seed addresses across various ISPs, allowing you to see exactly how your email is treated by each provider. Many ISPs distribute emails inconsistently—meaning the same email may land in the inbox for some users but go to spam for others.For example, an ISP might deliver:
30% of your emails to the inbox
70% to the spam folder
Additionally, ISPs analyze recipient engagement (opens, clicks, replies, and deletions) to adjust future placements. Over time, emails that initially land in spam may be dynamically moved to the inbox—or vice versa—depending on how users interact with them. This dynamic filtering makes ongoing testing critical for maintaining strong deliverability.
Important Considerations Before Running an Inbox Placement Test
To get the most accurate results, send each seed address a separate email.
Do NOT send all test emails using the “To” or “CC” fields—this is a major spam flag, as mass-sending to multiple recipients with different domains at once can be perceived as suspicious behavior.
If you use an ESP (Email Service Provider), send the test email exactly as you would in a real campaign to mimic real-world sending conditions.
If your email contains dynamic content, make sure each test email reflects how your actual audience would receive it.
Only send to opt-in users – Sending to purchased or scraped lists is a surefire way to get flagged.
Send only to engaged users – Many recommend focusing on 30-day openers and clickers, but this varies based on email frequency. If you send a monthly newsletter, filtering by 30-day engagement isn’t always practical.
Remove unsubscribed users and feedback loop (FBL) complaints – ISPs track user complaints; repeated issues hurt your sender reputation.
Ensure proper authentication – Set up SPF, DKIM, and DMARC records to verify your sending domain and prevent spoofing.
Follow ISP Postmaster Guidelines – Each ISP has its own rules for managing deliverability. See our guide for direct links to major ISPs’ best practices.
Warm up new domains and IPs – If you recently switched to a new sender domain or IP, gradually increase your sending volume to build a positive reputation.
BCL (Bulk Complaint Level) – A score from 0 to 9 indicating how much a sender resembles a bulk sender. Higher values (above 4) indicate higher likelihood of spam placement.
SCL (Spam Confidence Level) – Ranges from -1 to 9, with higher numbers meaning greater suspicion of spam. Emails with an SCL of 5 or higher are usually sent to spam.
SNDS (Smart Network Data Services) – Provides IP reputation insights, showing complaint rates and spam filtering behavior.
ICL (Inbox Confidence Level) – A proprietary Apple Mail score determining the likelihood of an email being placed in the inbox vs. spam. This is largely based on user engagement, sender authentication, and past delivery history.
Campaign Cleaner analyzes and optimizes your email content for better deliverability and engagement—helping you stay out of the spam folder and in the inbox.