Important Change to Activity Records in Marketo APIs

March 1, 2017 | by

Note: This post will be updated to reflect changes made to activity records returned by the API due to migration to new infrastructure.

Last Update: September 13, 2018

With the rollout of Marketo’s next-generation Activity Service beginning in September 2017, we will be unable to enforce the uniqueness or presence of the integer “id” field in activities, data value changes, or lead deletion records returned by Marketo’s APIs.

To avoid service disruptions for integrations which retrieve activity records, the id field should be treated as optional.  Cutover of this change will begin to affect subscriptions and upcoming release.

This change will affect the following endpoints:



The affected SOAP types are ActivityRecord and LeadChangeRecord.


The following examples show record types which will be affected.  In both examples, the effected field is called “id.”

Example REST Field: id

Example SOAP Field: id


Do I need to update my WSDL version if I’m using SOAP integration?

Yes.  The marketoGUID field will only be returned in activities when using the WSDL version 3.1 or later.  The new URI will follow this pattern: https://{munchkinId}  It may also be obtained through the Admin->Web Services menu in your subscription

When can I expect to see each change?

Beginning with our Q1 Minor Release on April 7th 2017, activity records retrieved via Marketo’s SOAP or REST APIs will include a new field called “marketoGUID”.  The value of this field will match the value of the “id” field, but will be a string type field.  Some time after the Q2 2018 release, the “id” field will stop being returned as part of these records, and the value of marketoGUID will become a 128-character string.

What do I need to do?

If you are responsible for code that deals with Marketo activities, you should determine whether your code relies on the presence or uniqueness of “id” field for Marketo activities, and then remove that requirement.  In an upcoming release, an additional string field called “marketoGUID” will be added.  “marketoGUID” should be considered the unique ID for retrieved activities when it becomes available.  If you are not, you should consult with your team and relay this message to the appropriate stakeholders.

Who will this change affect?

This change should only affect client and partner integrations which retrieve activity records from Marketo, and only if the integrations rely on either the presence and/or type of the “id” field in the response, or rely on the uniqueness of the field.  After the rollout of Orion AS, and the disabling of activity writes to MySQL, the “id” field will no longer be available and will be supplanted by a unique string id field.