Why do my emails end up in spam?
Understanding the filters and how to fix them.
The short answer
Email providers like Gmail, Outlook and Yahoo use increasingly strict filters to protect their users. A legitimate email can land in spam if the sender's domain isn't configured correctly — even if the message is completely harmless. The most common cause: missing or incorrect DNS records (SPF, DKIM, DMARC).
The main causes
1. Missing SPF record
The SPF record (Sender Policy Framework) tells receiving mail servers which servers are authorized to send email on behalf of your domain. If it's missing or incomplete, the receiving server has no way to verify the email is legitimate — and may mark it as potential spam.
Example of a valid SPF record:
v=spf1 include:_spf.google.com ~all
➜ Check yours with our email readiness tool.
2. Missing DKIM signature
DKIM (DomainKeys Identified Mail) adds a cryptographic signature to each email. This signature allows the receiving server to verify that the message hasn't been tampered with since it was sent. Without DKIM, your emails are more likely to be treated as suspicious.
➜ DKIM is configured in your email platform (Google Workspace, Microsoft 365, etc.) and published as a TXT record in your domain's DNS.
3. Missing or too permissive DMARC
DMARC ties SPF and DKIM together and defines a policy for what to do when a message fails both checks: none (monitor only), quarantine (send to spam) or reject (block completely). Since early 2024, Google and Yahoo require a DMARC record for bulk senders. Without one, your emails risk being blocked outright.
Minimal example:
v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com
4. Sender reputation
Email providers keep a reputation score for every IP address and domain that sends email. If your domain or IP has previously sent spam, had a high bounce rate, or if users frequently mark your emails as junk, your reputation score drops — and future emails are more likely to be filtered. Warming up a new domain (starting with small volumes and gradually increasing) helps build a good reputation.
5. Email content and formatting
Certain content triggers spam filters even when DNS records are perfectly configured: an overly promotional subject line ("FREE!", excessive caps, lots of exclamation marks), too many images and too little text, suspicious links, missing unsubscribe link for bulk emails, or an HTML/plain text ratio that's very unbalanced. Spam filters look at hundreds of signals simultaneously.
Practical checklist
➜ Check your domain's configuration with our email readiness tool.