Character limit in custom field configuration

On-premises Instances

In On-Premises instances, there is no strict limit on the number of characters allowed in custom field configurations. This means you can configure custom fields with significant data without worrying about platform-imposed limits.

Cloud Instances

In Jira Cloud instances, Atlassian imposes a limit of 240 KiB or ≈ 245 KB for custom field configurations. This limit is imposed to ensure performance and scalability of the cloud service.

This is the Atlassian documentation about Forge hosted storage key and object where you can find this information (under the paragraph “Forge hosted storage key and object size limits”): Platform quotas and limits.