Use the 123FormBuilder – Marketo integration to send leads to one or more lists from your Marketo account. Go to the Settings3rd Party Apps section of your form, hover over the Marketo logo and hit Add to install the application on your form. Provide your Rest API Key, Client Id and Client Secret to proceed to the customize settings phase.

Note: You need at least one existing mailing list in Marketo for the integration to work.

Connect | Customize

To retrieve the Client Id and Client Secret, you’ll need to create a custom service in your Marketo account. Here’s how you do it:

1. In your Marketo account, go to Admin and click on Users & Roles, on the left.

123formbuilder marketo integration

2. Click on the Role tab (on top) and hit New Role.

123formbuilder marketo integration

3. In the Create New Role lightbox, type in a Role Name and go to Permissions (third box below). Check the option Access API and deselect the sub-options below, except Read-Only Lead, Read-Write Activity and Read-Write Lead. Next, press Create.

123formbuilder marketo integration

4. Now go to the tab Users and click on Invite New User. Provide a name and email address of the API only user, select the newly created role and tick the checkbox API Only. In the end, click on Invite.

123formbuilder marketo integration

5. You’ll now be required to create a custom application. Go to AdminLaunchPoint and create a new service.

123formbuilder marketo integration

6. In the lightbox, enter a name and select an API Only user in the dropdown list below. Notice that only users that are API only are displayed. Hit Create to exit the lightbox and go to View Details to retrieve the Client Id and Client Secret needed for your 123FormBuilder – Marketo integration.

123formbuilder marketo integration

7. To find the Rest API, go to AdminWeb Services and you’ll find it within the Rest API box. It’s the series of characters displayed at End Point and Identity as shown in the example below:

123formbuilder marketo integration

This concludes the steps in retrieving the Rest API, Client Id and Client Secret for the 123FormBuilder – Marketo integration. Return to your 123FormBuilder account, go to your form, paste the three code in the Marketo application box and hit Connect to continue.

123formbuilder marketo integration

123formbuilder marketo integration

Go to Customize to set up your 123FormBuilder – Marketo integration. Here you can select one of the two available actions: Add subscriber and Unsubscribe email. Below, select a list from your Marketo account where new leads will be sent on submission. You can send the same lead to multiple lists on the same submission.

Use the Update existing subscriber option if needed and start mapping 123FormBuilder fields with Marketo fields and custom fields in the Field subsection. Remember to set the Email field as required on the form in order for the integration to work properly. In the end, use the Email Handling for problems that might occur during submission, such as a bad network connection on the submitter’s side that would prevent the lead to be created in Marketo.

Olivian Stoica
Olivian Stoica
Oli's enthusiasm for helping our fellow users led him to write thorough know-how articles and tutorials that would make form building a bliss on 123FormBuilder.


  1. Darcy Lechte says:

    Hey, is there a way to use Marketo lists to control who sees the contact form? For example if I have created a contact form for newsletter subscriptions that pops up on our page after 30 seconds. If the person is already subscribed to the newsletter is it possible for it not to pop up, and only pop up for people who are not subscribed? I understand this is a very specific request but would appreciate some help on understanding customisation for who is and is not eligible to see the pop up form.

    Thanks in advance,

    • Hello Darcy!

      I apologize for the late reply. May I suggest you use our contact form to receive a quick reply from one of our support representatives whenever you need assistance. Our Support Team can also be reached at or you can use Live Chat whenever one of our support specialists is logged in. You’ll find the Live Support widget on the bottom-right side of your screen when logged in your 123FormBuilder account.

      Regarding your questions, I’m sorry to say that we do not support such a feature, but you may suggest it in our feature requests list. Just fill out our suggest feature form with the feature you need and it will be published in our Feature Requests section, where other users may vote it.


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