Custom Authentication in Payloads lets you send a credential value either as a request header or as a URL query parameter. This guide shows how to configure a Custom Credential, assign it to a Payload, and verify the value is sent correctly.
Who this guide is for
This guide is for Salesforce admins and integration builders who need a non-standard authentication placement that is not covered by the dedicated API Key type.
Before you begin
Make sure you already have:
a Payload record which calls out to another system
a Custom Credential
an external endpoint you can inspect (for example, Beeceptor)
How to configure & test the Credential
Create a Custom Credential and choose placement mode
From your Integration, click New Credential, enter a name, set Type to Custom, then choose whether the value should be sent as a Header or Parameter.
This walkthrough uses Parameter mode.
Set Parameter Name and Parameter Value to match the target API requirement, then save the Credential.
Assign the Custom Credential to the Payload
Open your Payload, click Edit, and set Credential to your Custom Credential.
Run the Payload
Run the Payload and confirm the Job completes successfully.
Verify endpoint in the Job
Open the completed Job and confirm the endpoint includes the configured query parameter.
Verify request in the external system
In your external endpoint tool, confirm the received request includes the same query parameter.
What "done" looks like
Your setup is correct when:
the Payload runs successfully
the Job endpoint includes the configured custom parameter
the external system shows the same parameter in the received request
Summary
With Custom Authentication in Payloads, you can place credential values where the target API expects them, either as headers or URL parameters, while still managing the configuration centrally through the Credential record.