Summary
Contact List and DNC List file uploads are being migrated from the legacy Upload Service to Darth, which uses the public API for file upload requests. As part of this migration, new Darth upload permissions are required for users who upload Contact Lists or DNC Lists.
To ensure uninterrupted access, the required permissions will be automatically backfilled for users who already have the relevant Outbound permissions.
Effective Date
Tuesday, February 3, 2026
Details
Contact List Upload Migration and Permission Updates
Contact List and DNC List uploads are moving from a legacy, permissionless upload service to Darth, which enforces standard public API authorization controls. This change provides:
• Improved security through explicit, auditable permissions
• Consistency with existing Outbound and Public API permission models
• Improved reliability and scalability through the Darth service
We are migrating Contact List file uploads from the legacy Upload Service to Darth, which uses the public API for file upload requests.
As part of this change, new Darth upload permissions are required for users who upload Contact Lists or DNC Lists. To ensure continuity, we will automatically backfill the required Darth permissions for users who already have the relevant Outbound permissions.
New Permissions (Automatically Backfilled)
• Contact List Upload: outbound:contactList:upload
• DNC List Upload: outbound:dncList:upload
Backfill Logic
Contact permissions
If a user has:
• outbound:contact:add or
• outbound:contact:edit
They will be granted:
• outbound:contactList:upload
DNC permissions
If a user has:
• outbound:dnc:add or
• outbound:dnc:edit
They will be granted:
• outbound:dncList:upload
Contact List permissions
If a user has:
• outbound:contactList:add or
• outbound:contactList:edit
They will be granted:
• outbound:contactList:upload
DNC List permissions
If a user has:
• outbound:dncList:add or
• outbound:dncList:edit
They will be granted:
• outbound:dncList:upload
Customer Impact
No action is required for existing users.The required permissions will be backfilled automatically, ensuring uninterrupted access to Contact List and DNC List uploads after the migration.
Impacted Resources
Contact List file upload APIs
• Requests to upload Contact List files now route through the Darth service and require the outbound:contactList:upload permission.
DNC List file upload APIs
• Requests to upload DNC List files now route through the Darth service and require the outbound:dncList:upload permission.
Affected endpoints:
• POST /api/v2/outbound/contactlists/{contactListId}/contacts/upload
• POST /api/v2/outbound/dnclists/{dncListId}/dncentries/upload
Issue References
AUTHZ-1009
LM-3841
Contacts
@Mason Mansfield Please reply to this announcement with any questions. This helps the wider developer community benefit from the discussion. We encourage you to use this thread before contacting the designated person directly. Thank you for your understanding.