Mailgun tag for server Google tag manager

This is the Mailgun counterpart of the SendGrid recipe. The pattern is the same: an event arrives, a tag calls an HTTP API. The details differ, so check Mailgun's documentation. See also Slack notifications and server-side tagging as an alternative to Zapier.

What you need

• A Mailgun account and a verified sending domain.
• An API key.
• To know your region: the API host differs for the US and the EU.

Trusted

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The request

Mailgun's messages endpoint expects form-encoded fields and basic authentication, with api as the user name and your key as the password.

const sendHttpRequest = require("sendHttpRequest");
const encodeUriComponent = require("encodeUriComponent");
const toBase64 = require("toBase64");

const host = data.region === "eu" ? "api.eu.mailgun.net" : "api.mailgun.net";
const body = "from=" + encodeUriComponent(data.from) +
  "&to=" + encodeUriComponent(data.to) +
  "&subject=" + encodeUriComponent(data.subject) +
  "&text=" + encodeUriComponent(data.text);

sendHttpRequest("https://" + host + "/v3/" + data.domain + "/messages", (statusCode) => {
  statusCode === 200 ? data.gtmOnSuccess() : data.gtmOnFailure();
}, {
  method: "POST",
  headers: {
    "Authorization": "Basic " + toBase64("api:" + data.apiKey),
    "Content-Type": "application/x-www-form-urlencoded"
  },
  timeout: 5000
}, body);

Allow the Mailgun hosts in the template permissions and keep the key in a secure field.

Use it wisely

• Internal alerts and simple notifications: fine.
• Customer marketing: use an e-mail platform with consent records and unsubscribe handling.
• Do not put personal data into messages to third-party addresses without a basis.

Errors

A realistic example

A small store wants an internal e-mail whenever an order above a threshold arrives, so the owner sees it on her phone. It adds a tag to its server container that calls Mailgun's messages endpoint on purchase events above the threshold, using its verified EU domain and the EU host. The first test fails with a not-found error, because the tag used the US host. After switching to the EU host the message arrives, and the team adds a condition so only one message per order is sent. The recipe is simple, and the two mistakes it caught, region and duplicates, are the ones that most people make the first time they try it.

Keep it healthy

Log the response status for each send, and look at the failures once a week. Mailgun reports bounces and complaints in its dashboard, so check that your internal alerts are not landing in spam. If a key is rotated, update the secure field the same day.

Data in, clean out

Raw events in. Clean events out.

Open Tracked collects each event on your own domain, removes the noise and sends what is left to Meta, Google Ads, TikTok.

cookie expiredad blockermissing click IDlate event

MetamatchedGoogle AdsdedupedTikToksentYour reportclean

Frequently asked questions

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Written by

The Open Tracked team

We build Open Tracked: server-side tracking hosting, analytics and the tools around them, for stores that spend on ads. Questions about this guide, or an idea for the next one?

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