Gmail – Feedback Loop and postmaster: Settings and step-by-step tutorial

As of several years, Google Gmail’s Webmail has nailed its place as the leader in innovation. This big boy from Mountain View highlighted from the others by providing high-quality spam processing, as well as by developing a successive line of innovations in terms of ergonomics, including labels, email-organization through tabs, interface-built-in unsubscribing button, etc.

However, deliverability professionals and advertisers have experienced poor long-lasting tools, especially when compared to other Webmails, and specifically compared to Microsoft’s Hotmail. Lack of Feedback loops and lack of data from reputation, among others, have been the standard up until a little more than a year from now, when this situation changed dramatically.

Gmail’s Feedback loop, which has been tested as of late 2013 by certain ESPs and announced to be launched – still at a beta level and upon prior invitation- during the MAAWG held in February 2014, has been opened as of several weeks from now to all advertisers through its brand new ‘Postmaster’ site.

As many other similar platforms of the kind, offers email senders the possibility of receiving sending-related technical data as well as data from reputation. Within this article, we will guide you step by step to set up and become familiar with these new tools.

Background: SPF, DKIM and ReverseDNS.

It is important to remember that properly setting up your email at the authentication stage is highly relevant for you, and not only for the Google Postmatser tool. It is an imperative step, otherwise your email steam risks not to be taken into account by Google when generating data available in the postmaster. The aforesaid can be understood as:

  • You own a valid SPF record referencing all your email-sending IPs.
  • Your emails have been duly DKIM-signed with a given domain name under your management (access to DNS server).
  • Your IPs hold a valid ReverseDNS (PTR record) using— in priority— a domain name attached to a DKIM signature.

Adding a domain name to the Postmaster’s interface.

In order to add a domain name, it will be necessary to login to and click on the ‘+’ bottom-right on the screen: the pop-up screen will now display:


Enter the domain name to be set, and then click next. On the following screen Google will ask you to prove that you own the domain by adding a DNS TXT or a DNS record.


The update of specific DNS servers may require up to 24 hours. It is possible that you are required to await before being able to click on the ‘Verify’ button — it is of course possible to switch windows and going back to it later on—.

If you use several subdomains for each one of your different e-marketing campaigns, you will entitled to embed every single one of them, as well as the main domain name. This will empower you on one hand to monitor the performance of your domain names, and on the other, to have an overall view of the main domain.

Important: The here mentioned TXT embedding operations on your DNS have to be repeated for each Google user willing to access this data. If several users require access and that you run several subdomains, the creation of a new Google account reserved to your colleagues is likely to be the better solution.

Setting your emails in order to supply the Feedback loop.

The set up of your Google’s Feedback loop is done separately from the Postmaster interface. Data upload is done through the email header.

The Feedback-ID: line should be embedded in the email header. This Feedback-id is composed of 3 changing fields separated by the character ‘:’, as well as of a SenderId, which shall remain consistent across your email sending activity. The SenderId should count between 5 and 15 characters.

See the example here below:
Feedback-ID : VarA:VarB:VarC:MyBrand

Feedback-changing fields may be used to reference your mail stream into the following categories:

  • Marketing campaign name.
  • Mail type (newsletter, update, operational).
  • Database segmentation.
  • Other.

Within the Postmaster interface, you will be empowered to follow-up the complaint rate per field when one of this displays an unusual rate.

Here below a brief list of examples used by well-known advertisers:

  • LinkedIn – Feedback-ID: accept_invite_04:linkedin
  • Twitter – Feedback-ID: 0040162518f58f41d1f0:15491f3b2ee48656f8e7fb2fac:none:twitterESP
  • : Feedback-ID:

Important: Google does not aim to provide identification of whoever is reporting your campaigns, but to enhance you with an indicator useful to detect untruthfully campaigns, programs, etc.
However, if you attempt to identify the source of your complaints from the Feedback-Id, Google may simply cut you off from its data stream.

Google is against spammers.

Before discussing any further about the many features available in the Postmaster interface, it is important to point out that Google’s aim is not to help spammers. All data offered in this platform is only available to good-reputation senders respectful of Gmail’s rightful guidelines

Different dashboards available.

Spam rate.

It is one of the most relevant indicators offered by Google’s Postmmaster tool. You will be empowered to follow up completely the spam-rate percentage per domain name or subdomains on a daily basis.


IPs reputation.

Gmail categorizes the reputation of IPs into 4 different levels: Bad, Low, Medium et High.


By clicking on the colored area on the graph—for instance: the orange field ‘Medium’ on August 31st— You will see a pop-up list containing all IPS at this reputation level.

Domain reputation.

Just as for the reputation of IPs, domains fall as well into 4 different categories: Bad, Low, Medium and High.


Feedback Loop.

If you have properly set up your Feedback-Ids, you should be able to see data on this dashboard. It is important to remember that the main goal is to segment the many different email programs in order to easily identify your email marketing complaint sources. For instance, by using an ID of the acquisition source for your addresses, you will be empowered to verify in no time your acquisition partners who are generating full amounts of spam.


This graph represents the percentage of emails validating the many different authentication technologies:

  • SPF: Percentage of emails having validated the SPF on the domain itself according to the overall email stream sent for this domain.
  • DKIM: Percentage of emails having validated the DKIM on the domain itself according to the overall email stream sent for this domain, carrying a DKIM signature.
  • DMARC: Percentage of emails having implemented the DMARC procedure according to the emails having validated both SPF and DKIM on the domain.



It represents the percentage of incoming and outgoing emails running a TLS encrypted protocol.


Delivery errors.

This graph shows the percentage of the traffic having being rejected— temporarily or for good— at the threshold of Gmail’s SMPT servers. This dashboard is highly important especially at the stage of warm-up, or when you are reached by a technical failure.



Comments (0)

    Add a Comment