We are integrating the Genesys Cloud Web Messaging Guest API into our custom portal to allow customers to submit support tickets with attachments. The requirement is strict regarding data integrity. We need to enforce specific MIME types and file size limits before initiating the upload process via the API.
The current implementation attempts to upload attachments directly. However, we found that the standard Web Messaging endpoints do not support direct multipart/form-data uploads for attachments in the same way email or media endpoints do. We are looking for the correct flow to handle MIME type validation and file size limits.
The issue arises when the client sends a file with a MIME type that is technically valid but not supported by Genesys Cloud for messaging attachments, such as application/x-executable or certain archive formats. The API returns a 400 Bad Request with a generic error message that does not specify the exact constraint violation. We want to validate these constraints on our side to provide a better user experience.
The documentation mentions size limits but does not provide a full list of accepted MIME types or the exact byte limit for attachments in Web Messaging conversations. We are currently guessing a 5MB limit based on general guidelines, but this is not confirmed.
Has anyone successfully implemented client-side validation for these constraints? We are looking for the definitive list of allowed MIME types and the exact maximum file size allowed for the Guest API upload endpoint. We need to ensure our validation logic matches the platform’s internal checks to avoid unnecessary API calls and failed uploads.