How can I intentionally deliver emails to the spam folder?
Matthew Whittaker
Co-founder & CTO, Suped
Published 8 Aug 2025
Updated 15 Aug 2025
9 min read
While most email senders strive for inbox delivery, there are instances, typically for specific testing or highly niche, conceptual projects, where intentionally routing emails to the spam folder might be the goal. This approach is unusual, and it's crucial to understand the significant risks and potential negative repercussions for your sender reputation and the underlying infrastructure. However, if you are wondering how to achieve this, it involves understanding and, in essence, reversing the best practices for email deliverability.
Mailbox providers (MBPs) like Gmail, Yahoo, and Microsoft Outlook employ sophisticated spam filters. These filters evaluate numerous factors to determine if an email is legitimate or spam. To intentionally trigger these filters, you need to introduce elements that are highly correlated with unsolicited bulk email (UBE). This guide will outline several methods to achieve this, covering technical configurations, content manipulation, and sender reputation factors.
Technical tactics for spam folder delivery
Technical tactics for spam folder delivery
One of the most direct ways to ensure an email hits the spam folder is to use the Generic Test for Unsolicited Bulk Email (GTUBE). This is a standardized string of characters designed specifically to trigger spam filters, particularly SpamAssassin. Including the GTUBE string in the email body will almost certainly mark it as spam by filters that recognize it.
Generic Test for Unsolicited Bulk Email (GTUBE) Stringtext
Another powerful method involves manipulating your email authentication records. If you explicitly fail SPF, DKIM, or DMARC, you can significantly degrade your sender reputation. For instance, sending from an IP address not authorized in your SPF record or with an invalid DKIM signature can signal spam to receivers. Intentionally misconfiguring these records is a sure way to raise red flags.
Sending from an IP address with a poor or non-existent reputation is also highly effective. Many shared hosting or cheap Virtual Private Server (VPS) providers may have IP ranges frequently used by spammers. Opting for such an IP, or deliberately using an IP that is already on a known email blacklist (or blocklist), will almost guarantee your emails go to spam or are outright rejected. Some blocklists, like Spamhaus PBL, list IPs that should not be sending email directly to mail servers, further impacting deliverability to the inbox.
You could also use a domain with a historically poor reputation. If the domain itself has been associated with spamming activities in the past, or if it lacks proper DNS records like MX, A, or PTR records, it will be viewed with suspicion. Sending from a newly registered domain without a proper warming-up period can also contribute to spam folder placement, as new domains often lack the established trust of older ones.
Content and behavioral triggers
Content and behavioral triggers
The content of your email plays a huge role in its deliverability. To trigger spam filters, use excessive capitalization, exclamation points, and suspicious phrases commonly found in spam, like “free money,” “act now,” or “Nigerian prince.” Including a high number of images relative to text, or using images without accompanying alt text, can also increase the spam score. Avoid personalization and make the email look as generic as possible.
Subject lines are another critical area. Using deceptive or highly suspicious subject lines, such as those that imply urgency or include common spam phrases, can immediately flag your email. A blank subject line is also highly suspicious and often results in spam folder placement, as outlined by email etiquette resources. Misleading subject lines that don't match the content are also a strong indicator of spam.
Sending to unengaged or questionable email lists will quickly erode your sender reputation. This includes purchased lists, old lists with many inactive addresses, or lists obtained without explicit consent. When recipients don't open your emails, mark them as spam, or unsubscribe, it signals to mailbox providers that your emails are not desired. This negative engagement significantly impacts your sender score and increases the likelihood of future emails landing in the spam folder, or even being outright blocked.
Furthermore, a high bounce rate, especially a high hard bounce rate, tells mailbox providers that you are sending to invalid addresses, a common characteristic of spammers. Ignoring unsubscribe requests or making the unsubscribe process difficult also contributes to recipients marking your emails as spam. This can be directly contrasted with best practices for avoiding spam filters.
Reputation degradation strategies
Reputation degradation strategies
To severely impact your sender reputation, you could engage in practices that are actively harmful to it. Sending emails to spam traps is one of the quickest ways to get blocklisted (blacklisted). Spam traps are email addresses used by internet service providers (ISPs) and anti-spam organizations to identify senders of unsolicited email. They are typically dormant or invalid addresses that should never receive legitimate mail. Sending to them is a strong indicator of questionable list acquisition practices or outright spamming.
A high complaint rate, where recipients manually mark your emails as spam, is a direct signal to MBPs that your mail is unwanted. While a few complaints might be tolerated, consistent high complaint rates will cause your emails to be routed directly to the spam folder, or even result in your domain or IP being put on a blocklist. This is a crucial metric that mailbox providers monitor closely to protect their users.
You can also use URLs in your email content that are known to be associated with spam or phishing. If these URLs are already on domain blocklists (blacklists), your email will likely be flagged immediately. This is a particularly effective method if the goal is to trigger content-based spam filters.
Failing to properly configure reverse DNS (PTR records) for your sending IP address, or having mismatched forward and reverse DNS entries, can also contribute to a poor sender reputation. Many email servers perform reverse DNS lookups as a basic spam check, and a failure here is often a red flag.
The consequences and risks
The consequences and risks
While you might have a specific reason for trying to send emails to the spam folder, it's vital to recognize the severe and lasting consequences this can have. The email ecosystem is designed to penalize behavior that looks like spam. Intentionally engaging in such practices can lead to your sending IPs and domains being added to major public and private blacklists (blocklists).
Once your domain is on an email blacklist, it becomes extremely difficult to send legitimate emails from that domain or IP in the future. The damage to your sender reputation can take months, or even years, to repair, if it's possible at all. Even if your initial goal is to reach the spam folder, continued negative signals will eventually lead to complete blocking, preventing any delivery whatsoever.
Furthermore, if you are using an Email Service Provider (ESP) or shared IP space, your actions can negatively impact other senders using the same infrastructure. ESPs have strict acceptable use policies, and intentionally generating spam signals will likely lead to your account being suspended or terminated. This is because your activities directly harm the deliverability of their other clients.
Even for experimental or artistic projects, the collateral damage to the shared email infrastructure can be significant. It's a fine line between landing in spam and being completely rejected, and the consequences for sender reputation are severe.
The risks of intentional spamming
Intentionally triggering spam filters is not without significant repercussions. Your domain and IP address can quickly be added to blacklists (or blocklists), making future legitimate email delivery virtually impossible. Mailbox providers may permanently block your sending infrastructure, and Email Service Providers (ESPs) will likely suspend or terminate your account due to policy violations. This isn't just about reaching the spam folder, but about enduring, severe reputational damage.
Views from the trenches
Best practices
Always maintain a clean, opt-in mailing list to ensure high engagement and low complaint rates.
Regularly monitor your email deliverability and sender reputation using dedicated tools.
Adhere strictly to email authentication standards (SPF, DKIM, DMARC) for all outgoing mail.
Provide clear and easy unsubscribe options to prevent spam complaints.
Common pitfalls
Sending emails with generic subject lines, excessive capitalization, or suspicious keywords.
Failing to implement or misconfiguring email authentication records like SPF, DKIM, or DMARC.
Sending from IP addresses with poor reputations or those known for spamming.
Ignoring high bounce rates or recipient complaints, which degrade sender reputation.
Expert tips
To achieve spam folder delivery for testing, use a dedicated, isolated environment to avoid impacting your primary sending reputation.
When testing, consider using specific strings like GTUBE that are designed to trigger spam filters without causing broader reputational damage.
Understand that continuous negative sending behavior will eventually lead to complete blocking, not just spam folder placement.
Focus on controlled experiments rather than prolonged intentional spamming to avoid irreversible consequences for your sending infrastructure.
Expert view
Expert from Email Geeks says that GTUBE (Generic Test for Unsolicited Bulk Email) is effective for SpamAssassin users, but its impact on other spam filters might vary.
2021-02-09 - Email Geeks
Expert view
Expert from Email Geeks says that including a URL listed on a Spamhaus domain blocklist is a serious method to get emails marked as spam, but it will negatively impact all involved infrastructure.
2021-02-09 - Email Geeks
Understanding intentional spam delivery
Successfully delivering emails to the spam folder involves deliberately undermining virtually every aspect of email deliverability best practices. From misconfiguring technical authentication to crafting content with spam triggers and engaging in poor list management, each step contributes to degrading your sender reputation.
While this might be an interesting exercise for testing or unique creative projects, it’s critical to remember the long-term damage this can inflict on your sending domain and IP. The line between spam folder delivery and outright blocking is thin, and recovery from a damaged reputation is often a long and arduous process.
Gmail, 
Yahoo, and 
Microsoft Outlook employ sophisticated spam filters. These filters evaluate numerous factors to determine if an email is legitimate or spam. To intentionally trigger these filters, you need to introduce elements that are highly correlated with unsolicited bulk email (UBE). This guide will outline several methods to achieve this, covering technical configurations, content manipulation, and sender reputation factors.
