You're in the right place! Segment documentation is now part of Twilio Docs. The content you are used to is still here—just in a new home with a refreshed look.

Using the Analytics.js Querystring API

Analytics.js can trigger Track and Identify events based on the URL query string. You can use this when tracking email click-throughs, social media clicks, and digital advertising.

Here are the optional query parameters to use:

Parameter	Description	Triggers
`ajs_uid`	The userId to pass to an Identify call.	This triggers an Identify call.
`ajs_event`	The event name to pass to a Track call.	This triggers a Track call.
`ajs_aid`	The `anonymousId` to set for the user.	This function returns the current `anonymousId`. When a value is passed, this function sets an `anonymousId` value.
`ajs_prop_<property>`	A property to pass to the Track call.	This won't implicitly trigger an event and is dependent on you also passing `ajs_event`. This property is included in the resulting Track call.
`ajs_trait_<trait>`	A trait to pass to the Identify call.	This won't implicitly trigger any call and is dependent on you also passing `ajs_uid`. This trait is included in the resulting Identify call.

For example, this URL creates the following events on the page:

http://segment.com/?ajs_uid=123456789abcd&ajs_event=Clicked%20Email&ajs_aid=abc123&ajs_prop_emailCampaign=First+Touch&ajs_trait_name=Karl+Jr.

Each trigger parameter is optional. You can pass up to 1 of each trigger parameter, as shown in the following example:

1analytics.identify('123456789abcd', { name: 'Karl Jr.' });
2analytics.track('Clicked Email', { 'emailCampaign': 'First Touch' });
3analytics.user().anonymousId('abc123');

How can I control query string processing?

The useQueryString option allows you to control the behavior of the query parameters. For example, you can entirely disable query string processing by setting useQueryString to false:

1analytics.load('<WRITE_KEY>', {
2  useQueryString: false
3})

You can also keep query string processing on, but enforce validation rules. For example:

1analytics.load('<WRITE_KEY>', {
2  useQueryString: {
3    // set a pattern for anonymousId 
4    aid: /([A-Z]{10})/,
5    // set a pattern for userId
6    uid: /([A-Z]{6})/
7  }
8})