Sending events

Overview

This guide explains how to format and send requests to the Google Analytics Measurement Protocol.

Sending events

To send an event, make an HTTP POST request to the following endpoint:

POST /mp/collect HTTP/1.1
HOST: www.google-analytics.com
Content-Type: application/json
<payload_data>

Note: The Measurement Protocol for Google Analytics 4 only supports POST requests.

Required parameters

A valid request requires two sets of parameters that vary if you're using Firebase or gtag.js:

Firebase gtag.js

1. URL parameters

   • api_secret - Required. An API SECRET generated in the Google Analytics UI. To create a new secret, navigate to:
     Admin > Data Streams > choose your stream > Measurement Protocol > Create

   See query parameters for the full reference.

2. JSON body

   • user_id - Optional. A unique identifier for a user. See User-ID for cross-platform analysis for more information on this identifier.

     Note: user_id may only contain utf-8 characters.

   • events - Required. An array of event items.

   See JSON POST BODY for the full reference.

Note: To send more than one event in one request, include multiple events in the events entry.

Recommended parameters for reports

In order for user activity to display in standard reports like Realtime, engagement_time_msec and session_id must be supplied as part of the params for an event.

Example:

{
"client_id": "x",
"events": [
  {
    "name": "offline_purchase",
    "params": {
      "engagement_time_msec": "100",
      "session_id": "123"
    }
  }
]
}

While session_start is a reserved event name, creating a new session_id will effectively create a new session without the need to send session_start.

Note: Understand how sessions are counted.

Send an event

Firebase gtag.js

To send a tutorial_begin event, make the following request:

Limitations

• Requests can have a maximum of 25 events.
• Events can have a maximum of 25 parameters.
• Events can have a maximum of 25 user properties.
• User property names must be 24 characters or fewer.
• User property values must be 36 characters or fewer.
• Event names must be 40 characters or fewer, may only contain alpha-numeric characters and underscores, and must start with an alphabetic character.
• Parameter names (including item parameters) must be 40 characters or fewer, may only contain alpha-numeric characters and underscores, and must start with an alphabetic character.
• Parameter values (including item parameter values) must be 100 characters or fewer.
• Item parameters can have a maximum of 10 custom parameters.
• The post body must be smaller than 130kB.