This article provides more information on the character limit for textarea fields in the Job Application.
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SAP SuccessFactors Recruiting Management
The textarea field has a 4000-character limit for non-Mobile Apply instances and a 1024-character limit for Mobile Apply instances.
Mobile Apply, in this case does not mean an application made via a mobile phone or the career site being accessed via a mobile phone. Mobile Apply instances are those instances with the following settings enabled: Admin Center > Manage Recruiting Sites > Enable V12 External Career Site > Enable Mobile Apply.
When the instance has Mobile Apply and the textarea field is populated with more than 1024 characters, a message similar to 'Answer size should be 1024 character or less' will appear.
Note: The Implementation guide only mentions textarea as 'Multiple lines of alphanumeric text with a 4000-character limit' but this information is incomplete. The 4000-character limit only applies for non-Mobile Apply instances.
Implementation Guide - Job Application Field Definition: Attributes
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