Retool's Slack integration now supports the files.getUploadURLExternal and files.completeUploadExternal APIs for uploading files. Slack ended support for their files.upload API on March 11, 2025, and this endpoint is no longer available in the Retool Slack integration.| Retool Changelog
As of March 12, 2025, this workaround is no longer required. Refer to Updates to Slack connector to support file upload for more information.| Retool Changelog