Which mailbox providers report spam complaints back to ESPs?

Summary

Major mailbox providers such as Gmail, Yahoo, AOL, and Microsoft (Hotmail/Outlook.com) offer Feedback Loops (FBLs) that report spam complaints back to email senders. These FBLs are essential for maintaining a good sender reputation and improving email deliverability. Apple and most business mail systems typically do not report spam complaints. While some providers offer FBLs, they might not report 100% of complaints. Setting up these FBLs requires authentication and adherence to specific guidelines. Complaint rates are a critical factor influencing email deliverability; high complaint rates can lead to emails being junked or blocked.

Key findings

Major FBL Providers: Gmail, Yahoo, AOL, and Microsoft (Hotmail/Outlook.com) are the key providers offering feedback loops.
Non-Reporting Providers: Apple and most business mail systems generally do not report spam complaints.
Partial Reporting: Many providers with FBLs may not report 100% of spam complaints.
Importance of FBLs: Feedback Loops are crucial for monitoring complaint rates and maintaining a positive sender reputation.
Complaint Rate Impact: High complaint rates, especially from major providers, negatively impact email deliverability.

Key considerations

FBL Setup Requirements: Setting up FBLs requires authentication, adherence to guidelines, and specific header configurations.
Comprehensive Monitoring: Utilizing multiple FBLs is necessary for comprehensive coverage across different providers.
Proactive Complaint Management: Actively monitoring and addressing complaint rates is vital for preventing emails from being marked as spam or blocked.
Reputation Impact: Consistent monitoring and management of spam complaints are crucial for maintaining a good sender reputation and deliverability.

What email marketers say
10Marketer opinions

Various mailbox providers offer feedback loops (FBLs) to report spam complaints back to email senders, enabling them to maintain good sender reputation and improve email deliverability. Major providers offering FBLs include Gmail, Yahoo, AOL, and Microsoft (Hotmail/Outlook.com). Apple and most business mail systems typically do not report spam complaints. Some systems don't report 100% of complaints. Setting up FBLs with major providers is crucial for tracking and addressing spam complaints.

Key opinions

Major FBL Providers: Gmail, Yahoo, AOL, and Microsoft (Hotmail/Outlook.com) are key providers offering feedback loops to report spam complaints.
Non-Reporting Providers: Apple and most business mail systems generally do not report spam complaints.
Incomplete Reporting: Many providers do not report 100% of spam complaints.
Feedback Loop Importance: Feedback Loops are critical for senders to monitor complaint rates and maintain a good sender reputation.

Key considerations

FBL Setup: Setting up feedback loops with major providers requires authentication and adherence to specific guidelines.
Complaint Rate Monitoring: Monitoring complaint rates, typically available through FBLs, is essential for maintaining good email deliverability.
Reporting Accuracy: Be aware that not all spam complaints are reported, even by providers that offer FBLs.
Sender Reputation: High spam complaint rates negatively impact sender reputation and email deliverability.

Marketer view

Email marketer from Mailjet shares that FBLs are offered by major mailbox providers, including Gmail, Yahoo, and Microsoft. They require senders to authenticate their email and adhere to specific guidelines to participate.

July 2021 - Mailjet

Marketer view

Email marketer from Litmus explains that monitoring complaint rates, typically available through FBLs, is essential for maintaining good email deliverability. High complaint rates negatively impact sender reputation.

September 2023 - Litmus

Marketer view

Email marketer from SparkPost shares that monitoring complaint feedback from mailbox providers is crucial for maintaining good sender reputation. They also indicate that Gmail, Yahoo, AOL, and Microsoft are key providers offering FBLs.

August 2022 - SparkPost

Marketer view

Email marketer from Reddit states Gmail, Yahoo, AOL, and Microsoft (Outlook.com/Hotmail) are the main providers offering feedback loops.

December 2023 - Reddit

What the experts say
2Expert opinions

Feedback Loops (FBLs) are mechanisms that allow email senders to receive spam complaints from Internet Service Providers (ISPs). Complaint rates are a critical factor that mailbox providers use to filter mail, with high complaint rates from providers like Gmail and Microsoft leading to emails being junked or blocked.

Key opinions

Feedback Loops (FBLs): FBLs allow senders to receive spam complaints from ISPs, helping maintain deliverability.
Complaint Rate Impact: High complaint rates, especially from major providers like Gmail and Microsoft, negatively affect email deliverability.

Key considerations

FBL Participation: Understanding which ISPs participate in FBLs is crucial for managing sender reputation.
Complaint Rate Management: Actively monitoring and addressing complaint rates is vital to prevent emails from being marked as spam or blocked.

Expert view

Expert from Word to the Wise describes complaint rates from users as a critical factor mailbox providers use to filter mail. High complaint rates from providers such as Gmail and Microsoft result in emails being sent to junk or blocked.

July 2024 - Word to the Wise

Expert view

Expert from Spamresource.com explains that Feedback Loops (FBLs) are a method for email senders to receive spam complaints from ISPs. The major participants are detailed in the linked article.

April 2024 - Spamresource.com

What the documentation says
3Technical articles

Gmail, Microsoft (Hotmail/Outlook.com), and Yahoo offer Feedback Loop (FBL) programs that allow email senders to receive reports of user complaints marked as spam. Google's Gmail FBL helps identify problematic campaigns. Microsoft's SNDS provides data on IP addresses, including complaint rates. Yahoo allows senders to use their Complaint Feedback Loop to receive spam complaint reports. These programs require specific setups and headers to access the data.

Key findings

Gmail FBL: Google provides the Gmail Feedback Loop for identifying campaigns causing spam complaints.
Microsoft SNDS: Microsoft's Smart Network Data Services (SNDS) offers complaint rate data for Hotmail and Outlook.com.
Yahoo Complaint Feedback Loop: Yahoo offers a Complaint Feedback Loop program to receive reports of user complaints.

Key considerations

Setup Requirements: Setting up these FBLs requires specific headers and configurations in your emails.
Data Usage: The data from these programs can be used to improve email deliverability and sender reputation.
Provider Coverage: Each program covers a specific mailbox provider (Gmail, Microsoft, Yahoo), so you need to use multiple to get comprehensive coverage.

Technical article

Documentation from Yahoo explains that senders can use their Complaint Feedback Loop program to receive reports of user complaints marked as spam in Yahoo Mail.

November 2021 - Yahoo

Technical article

Documentation from Google Postmaster Tools details the Gmail Feedback Loop (FBL), which allows senders to identify campaigns causing spam complaints. It requires setting up specific headers in your emails.

November 2022 - Google Postmaster Tools

Technical article

Documentation from Microsoft SNDS (Smart Network Data Services) describes a service that provides data about your sending IP addresses, including complaint rates from Hotmail and Outlook.com users.

September 2022 - Microsoft SNDS