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Campaign Monitor was invited by Gmail’s team to enter an early, pre-beta program of their Feedback Loop (FBL) in December, to help them work through any issues they had prior to rolling it out widely. We were privileged to be part of a select handful of ESPs that were invited to assist Gmail in their trials of the FBL – and since, we’ve not only worked together to keep our service more secure, but learnt a few things about how Gmail handles spam complaints.

For a little background, the FBL is a program in which Email Service Providers (ESPs) like Campaign Monitor work together to prevent email spam and abuse. It is only available to ESP’s that are accepted to join – bulk senders cannot apply directly. As part of our part in the program, we keep a careful watch on what is being sent from our servers for the purposes of stopping and preventing bad behavior, provide best practice advice and help improve customers’ email strategies where they are causing Gmail concern.

Making email safer for everyone

The result of the FBL is a more unified approach to improving services for both email senders and receivers alike. No matter how hard we try, and what technologies we implement, there is always room to improve our efforts in keeping our service spam and abuse free. So, while it isn’t always possible to stop a bad sender from starting an account, the FBL provides another layer of protection. For example, at least on one occasion, a known phisher was caught early on by Gmail – who alerted us, so we could ensure they couldn’t send any malicious emails and potentially, affect delivery rates for other customers using Campaign Monitor.

Learning from the ‘Loop

In the time we’ve collaborated with Gmail, we’ve learned a lot about their anti-spam efforts, both internally and with senders like ourselves. For starters, the Feedback Loop is not a traditional one in the sense that it does not use the Abuse Reporting Format (ARF) and as a result, we don’t get the same level of detail as we do from services like Outlook, AOL or Yahoo! Mail. These webmail providers give you the full details of the complainant and reasons for marking an email as spam, whereas Gmail is more discriminating in the information they provide.

That said, Gmail does make things terribly easy for ESPs, in some ways. For example, the feedback we do receive allows us to determine whether there are issues with a sender’s program overall, or a specific campaign, or even specific lists or content. Through a series of identifiers, Gmail enables us to help customers identify where their delivery problems lie, so we can work together constructively.

Here at Campaign Monitor, we believe very strongly in working with all the major ISPs and will go the extra mile to adapt to their requirements, as rapidly as possible. It is something we have been doing for 10 years. Therefore we did not have an issue with mobilizing quickly to cover Gmail’s technical requirements – including, but not limited to X-Feedback-ID headers and dual DKIM signing. It did require we upgrade software and make some changes to our code to facilitate, but the payoff has been worth it, especially with customers getting feedback on their email program. As a result, we’ve been able to resolve those issues and see much better deliverability results at Gmail and other providers.

Whilst in the pre-beta trials, we had only enrolled email senders that do not authenticate their own mail and did not sign with DKIM. We have now fully implemented the FBL, which means over 100,000 email senders are now benefiting from better communication between Gmail and Campaign Monitor.

If you have any questions about how we’re working with ISPs to improve the email experience for both senders and recipients, please feel free to post away in the comments below, or contact our team directly. We’ll do our best to answer them.


This blog provides general information and discussion about email marketing and related subjects. The content provided in this blog ("Content”), should not be construed as and is not intended to constitute financial, legal or tax advice. You should seek the advice of professionals prior to acting upon any information contained in the Content. All Content is provided strictly “as is” and we make no warranty or representation of any kind regarding the Content.
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