Analytics.js 2.0 (Beta)

Analytics.js 2.0 is recommended for use in staging

Analytics.js 2.0 was built with backwards compatibility in mind. However, Segment recommends thorough testing in a Staging environment before you upgrade your production source.

Analytics.js is Segment’s most popular library source. This new major version has been re-engineered to be more performant and provide greater extensibility. It is fully backwards compatible with the previous version of Analytics.js.

Benefits of Analytics.js 2.0

The Analytics.js 2.0 Beta provides two key benefits over the previous version.


Analytics.js 2.0 provides a reduction in page load time, which improves overall site performance. Its package size is ~70% smaller than the previous Analytics.js.

There are many factors that impact page load time, including page weight, network conditions, and hosting locations.

Developer experience

Analytics.js 2.0 introduces new ways for developers to augment events throughout the event timeline. This enables teams to support:

  • New privacy and consent controls before an event occurs
  • Enriching events with additional customer or page context in-flight using middleware
  • Collecting better metrics related to deliverability after a message is sent

Start using Analytics.js 2.0

Analytics.js is released as a Public Beta, on an opt-in basis, per source. The updated code is delivered through your existing snippet, so there’s no need to update code on your site.

To opt in:

  1. Navigate to the Settings tab of the javascript source you want to enable.
  2. Enable the Analytics 2.0 toggle.

Once enabled, after 5 minutes or less, the updated code is delivered.

Disable Analytics.js 2.0

To revert back to the previous version of Analytics.js, disable the Analytics 2.0 toggle on any source you’ve enabled it.

Cases that require manual upgrade

There are two cases where upgrading to Analytics.js 2.0 requires manual effort beyond enabling the Analytics.js 2.0 toggle.

When using in-domain instrumentation CDN aliasing

If the source you intend to upgrade uses the in-domain instrumentation as well as a custom “Alias for analytics.js”, then you should update the AJS snippet to the latest version (4.13.2 or higher) before you toggle on Analytics.js 2.0.

When using a strict content security policy on the page

Analytics.js 2.0 asynchronously loads different pieces of the library as needed. If the source you’re upgrading uses a strict Content Security Policy (CSP) that allows Javascript to be downloaded from specific locations, then you need to update the CSP to account for all the pieces used for Analytics.js 2.0. Therefore, beyond allowing the main analytics.min.js script, you should allow the following paths in your CSP:


Open source libraries

Analytics.js 2.0 includes the following open source components:

uuid v2.0.0 ( Copyright Luke Edwards <> ( License: MIT License, available here:

component-url v0.2.1 ( Copyright (c) 2014 Component License: MIT License, available here:

dset v2.0.1 ( Copyright (c) Luke Edwards <> ( License: MIT License, available here:

js-cookie v2.2.1 Copyright (c) 2018 Copyright 2018 Klaus Hartl, Fagner Brack, GitHub Contributors   License: MIT License, available here:

md5 v2.3.0 ( Copyright (c) 2011-2012, Paul Vorbach. Copyright (c) 2009, Jeff Mott. License: BSD-3-Clause “New” or “Revised” License, available at:

unfetch v4.1.0 ( Copyright (c) 2017 Jason Miller License: MIT License, available at:

This page was last modified: 10 Mar 2021

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