If a large number of subscribers mark your emails as spam, it can seriously damage your sender reputation—even leading to your emails being blocked by inbox providers entirely. These spam complaints not only affect your current campaign but also future deliverability, even for highly engaged subscribers.

This guide outlines best practices to reduce spam complaints and ensure your emails land where they belong: the inbox.

When a subscriber clicks “Report as Spam,” it signals to mailbox providers that:

• Your email is unwanted

• Your sending domain might not be trustworthy

• Future emails from you should be filtered out

High spam complaint rates (0.30% or higher) can trigger deliverability issues or suspension of your sending privileges.
​

• Use explicit opt-in methods such as signup forms or landing pages

• Avoid importing email contacts without consent

• Never purchase email lists (violates Flodesk’s acceptable use policy and increases spam risks)

The more intentional your list-building process, the less likely recipients are to report your emails.
​

Subscribers should instantly recognize who the email is from.

• Set a From Name that matches your brand or personal identity

• Use a verified custom domain email address, not a free address (like Gmail)

You can configure your sender info in Account settings > Email setup in Flodesk.

• The unsubscribe link should be easy to find and easy to read

• Avoid hiding it in small text or using colors that make it hard to see

When users can’t find an unsubscribe link, they often mark the message as spam instead. Allowing subscribers to easily opt out is healthier than forcing disengagement.

Sending emails to people who don’t engage increases your risk of spam complaints.

What to do:

• Create a “Less engaged” segment using Flodesk filters

• Exclude this segment from regular campaigns

• Consider running a re-engagement campaign for this group later

Focusing on active subscribers keeps your list healthy and lowers complaint rates.

If it’s been a while since you last emailed, remind your audience how they joined your list.

Include a brief note:

“You’re receiving this email because you downloaded [Freebie Name] or signed up for updates at [Your Website].”

Jogging their memory helps reduce confusion—and spam reports.

Email content tips:

• Don’t use misleading subject lines

• Avoid trigger phrases like “Act now,” “Click here,” or “Risk-free”

• Maintain a balanced text-to-image ratio

• Use alt-text for images so emails are readable even when images are blocked

Emails that consist mostly of images (with little text) can appear suspicious, especially if they don’t load properly.

In Flodesk, you can view spam complaints in the Email report > Bounces, Unsubscribes, Spam section.

Important note: Gmail and some other inbox providers do not send a specific notification to email marketing services like Flodesk, when a person marks an email as spam, so the spam count within your Flodesk email analytics may be underreported.

To get more accurate spam complaint data, set up Google Postmaster Tools:

• Track spam complaint rates from Gmail users

• Monitor domain reputation over time

• Get actionable insights into how Gmail views your emails

Learn how to set up Google Postmaster Tools.

Keeping spam complaints low protects your sender reputation, improves deliverability, and helps build long-term trust with your audience.