Final answer:
In order to update a custom field and make a callout when a new account is created, a trigger and an Apex class are used. The class handles record updates and the asynchronous external callout, including error handling.
Step-by-step explanation:
To address the scenario where a custom field on an unrelated record needs to be updated and a callout made to an external platform whenever a new account is created, a programmatic solution is required.
The solution could involve writing a trigger in a system like Salesforce, and using an Apex class to handle the logic for the update and callout.
Below is a step-by-step explanation of how this can be implemented:
Create a trigger on the account object which fires after a new account is created.
The trigger invokes an Apex class that contains the logic for checking the related records that need updating.
The Apex class performs the necessary update on the custom field of the unrelated record.
After updating the record, the Apex class makes an HTTP callout to the external platform, typically within an asynchronous operation such as a Future method or Queueable class to avoid delaying the transaction and to handle callout restrictions in Salesforce.
Implement error handling in the Apex class to manage any issues that may arise during the operation.
It is important to ensure that the external callout adheres to the callout limits and best practices, such as using named credentials for endpoint storage and handling bulk operations effectively.