Backup files are downloaded over HTTPS, not through an API endpoint. Sign in with the username and password of the index, the ones in its Security tab.
Folder
https://backup.opensolr.com/INDEX_NAME/One file
https://backup.opensolr.com/INDEX_NAME/FILE_NAMESign inThe HTTP Basic Auth username and password of the index: HTTP Basic Auth.
In the panelDownload backup files
01 · Find the file name
Call get_backup_files_list, or open the folder of the index in a browser: it lists every backup file.
02 · Example
curl -u "INDEX_USERNAME:INDEX_PASSWORD" -o my_index_10_11_2026-02.00.09.tar \ "https://backup.opensolr.com/my_index/my_index_10_11_2026-02.00.09.tar"
A new index starts with the username opensolr and your master API key as its password. If you changed them, use the new ones.
03 · Related
Make a backup: create_backup. Restore one: restore_backup.
How long backup files are kept, and the steps in the Control Panel: Download backup files.