Complaint Handling

What complaint handling is

A complaint happens when a recipient clicks “report spam” or “junk” on your message. Mailbox providers treat complaint rates as one of the strongest signals about whether a sender is wanted. Gmail and Yahoo’s bulk-sender requirements specifically expect complaint rates to stay low.

Complaint handling means three things: receiving the complaint data where providers offer it, suppressing that person from all future marketing immediately, and monitoring the overall rate so a rising trend is caught early. It also means making unsubscribing easier than complaining, which reduces complaints in the first place.

Unlike a bounce, a complaint comes from a real person who received your mail and didn’t want it. That makes it one of the most direct signals you get about how your emails are perceived.

Signs you need better complaint handling

• Google Postmaster Tools shows a spam rate that is rising or high.
• Your sending provider has flagged your complaint rate.
• People who complained keep receiving campaigns from another list.
• Your emails have no one-click unsubscribe, or the unsubscribe link is hard to find.
• You only look at complaints after a campaign has already caused damage.

Where complaint data comes from

Complaint data doesn’t arrive the same way from every provider. Some, including Yahoo, offer feedback loops that send a report for each complaint about DKIM-signed mail from registered domains. Cloud platforms such as Amazon SES pass complaint notifications from participating providers. Gmail doesn’t send per-recipient complaint reports; instead, Google Postmaster Tools shows an aggregate spam rate for your domain. Microsoft SNDS provides IP-level data including complaint information.

Because coverage is incomplete, complaint handling also depends on offering a List-Unsubscribe header with one-click support, so recipients who want to stop receiving mail can do so from the inbox without reaching for the spam button.

What’s included

• Feedback loop registration where available, covered in detail in feedback loop configuration.
• Complaint notifications from cloud providers wired into your platform.
• One-click List-Unsubscribe headers on marketing mail, with unsubscribes processed promptly.
• Suppression of complainers across every list and brand you hold, not just the one that was reported.
• Synchronisation to your CRM so complainers aren’t re-imported.
• Monitoring of complaint rate per campaign and per provider, with alerts when it rises.
• A short review of which campaigns and segments drive complaints.

How we deliver it

1. Review current complaint data sources and what your platform does with them.
2. Register or configure each available complaint feed.
3. Add or fix one-click unsubscribe headers and test them in major inboxes.
4. Set global suppression rules and test with simulated complaints.
5. Set up dashboards and alerts on complaint trends.
6. Document coverage, including which providers report and which don’t.

Reducing complaints at the source

Suppression limits damage; prevention avoids it. Complaints usually come from people who don’t recognise the sender, receive more mail than expected, or never clearly agreed to it. Clear opt-in, a recognisable From name, a frequency people signed up for and an easy unsubscribe do more than any technical fix.

Complaint data by campaign and segment often shows a clear pattern: a particular sign-up source, an old segment re-mailed after a long gap, or a frequency jump. Acting on that pattern usually does more than any single technical change.

What affects timeline and cost

• Number of platforms, brands and lists.
• Which providers’ feedback loops apply to your audience.
• Integration with your CRM or application.
• Depth of monitoring and reporting required.

Common mistakes

Suppressing a complainer from one list while mailing them from another. Hiding the unsubscribe link, which pushes people to the spam button. Treating Gmail’s lack of per-message reports as a lack of complaints. Reviewing complaint rates monthly rather than per campaign.

Related: bounce handling, all email infrastructure services, the guide, and contact.

Frequently asked questions