Sales Loves MarketingA complaint, in email marketing, is when someone clicks "Report spam" or "Junk" on your message. It is the clearest signal a recipient can send that they don't want your email. Mailbox providers such as Gmail and Yahoo count these reports and use them to decide where your next campaign lands.
How do spam complaints work?
- A recipient opens their inbox and marks your message as spam.
- The mailbox provider records the complaint against your sending domain and IP address.
- If you have signed up for that provider's feedback loop, it sends you a copy of the complaint, usually in the standard Abuse Reporting Format. Yahoo, for example, runs a Complaint Feedback Loop for DKIM-signed mail. Gmail instead shows your overall spam rate in Postmaster Tools.
- Your email platform should suppress that address so you never mail it again.
Why do complaints matter?
Complaints are one of the strongest signals in deliverability. A high rate can push your email into spam folders for every recipient at that provider, not just the person who complained.
Both Gmail and Yahoo now publish limits:
- Gmail asks all senders to keep the spam rate in Postmaster Tools below 0.3%, and recommends staying under 0.1%. These requirements have applied since February 1, 2024. Senders of more than 5,000 messages a day to Gmail accounts must also support one-click unsubscribe.
- Yahoo sets the same 0.3% threshold for bulk senders, measured on mail delivered to the inbox. It also expects unsubscribe requests to be processed within two days.
How to keep complaints low and stay compliant
- Mail only people who opted in. Gmail's sender guidelines say to send only to people who signed up, to confirm each address, and never to buy email addresses from other companies.
- Make the sender obvious. Use a consistent, accurate From name and address so people recognise who is writing to them.
- Make leaving easy. Add a visible unsubscribe link and the one-click unsubscribe header defined in RFC 8058. An easy opt-out turns would-be complaints into unsubscribes.
- Send what you promised, at the frequency people signed up for.
- Segment and clean your list. Use list segmentation to send relevant content, and stop mailing people who haven't engaged in a long time.
- Avoid no-reply addresses. Give people a way to reach you.
- Follow the law. In the US, the FTC's CAN-SPAM guide requires truthful headers and subject lines, a physical postal address, a clear way to opt out and that opt-outs are honoured within 10 business days. In the EU and UK, GDPR and e-privacy rules set the consent requirements.
Customer complaints
Outside email, a complaint is any expression of dissatisfaction from a customer, about a product, a service or how they were treated. In sales and marketing, complaints often point to a gap between what was promised and what was delivered, so they are worth logging and tracing back to their cause.
Related terms
Frequently asked questions
What is an acceptable spam complaint rate?
Gmail asks all senders to keep the spam rate shown in Postmaster Tools below 0.3% and recommends staying below 0.1%. Yahoo also sets 0.3% as the threshold for bulk senders, measured on mail delivered to the inbox.
How do I see spam complaints?
Some mailbox providers send copies of complaints to senders who sign up for a feedback loop, for example Yahoo's Complaint Feedback Loop for DKIM-signed mail. Gmail shows an overall spam rate in Postmaster Tools instead of individual reports.
What is the difference between a complaint and an unsubscribe?
An unsubscribe tells you, the sender, that the person wants no more email. A complaint tells the mailbox provider that your email is unwanted, which can hurt delivery to everyone on that provider. Making unsubscribing easy turns many would-be complaints into unsubscribes.