How to use SFTP with cURL

When an older transfer job moves off plain FTP, cURL can keep the same basic upload and download workflow over SFTP without switching tools. That is useful for partner feeds, scheduled exports, and one-off file pulls that already depend on curl in scripts or automation.

With SFTP, the URL path is absolute by default, and the special /~/ prefix targets the remote account's home directory. cURL can list a directory with --list-only, send a file with --upload-file, and save a download locally with --output or --remote-name.

Authentication usually comes from an SSH key passed with --key, while the server identity still needs to match a trusted host key. Some curl builds ship without SSH support, so if the Protocols: line from curl --version does not include sftp, every SFTP command on this page fails with unsupported protocol until a curl build with SFTP support is used.

1. Check whether the local curl build supports SFTP before using an sftp:// URL.

   $ curl --version
   curl 8.19.0 (x86_64-pc-linux-gnu) libcurl/8.19.0 OpenSSL/3.5.4 zlib/1.3.1 libssh2/1.11.1 nghttp2/1.67.0
   Release-Date: 2026-03-11
   Protocols: dict file ftp ftps gopher gophers http https imap imaps ipfs ipns ldap ldaps mqtt mqtts pop3 pop3s rtsp scp sftp smb smbs smtp smtps telnet tftp ws wss
   Features: alt-svc AsynchDNS HSTS HTTP2 HTTP3 IPv6 Largefile libz SSL threadsafe UnixSockets

   If the Protocols line does not contain sftp, use a curl build with SSH support before continuing.

2. List the remote target directory before transferring anything so the path is confirmed first.

   $ curl --silent --show-error --list-only --user syncbot: --key ~/.ssh/id_ed25519 sftp://sftp.example.net/~/incoming/
   archive
   reports

   In SFTP URLs, /~/incoming/ means the incoming directory under the remote account's home directory. Some servers also return . and .. in a name-only listing.

3. Upload the local file to the same SFTP directory with the remote name that should exist on the server.

   $ curl --user syncbot: --key ~/.ssh/id_ed25519 --upload-file ./daily-export-2026-04.csv sftp://sftp.example.net/~/incoming/daily-export-2026-04.csv
     % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                    Dload  Upload   Total   Spent    Left  Speed
   100    22    0     0  100    22      0    531 --:--:-- --:--:-- --:--:--   531

   Replace ./daily-export-2026-04.csv with the local file that already exists on the system. If the destination directory does not exist yet, add --ftp-create-dirs.

4. List the directory again and confirm that the uploaded filename now appears on the server.

   $ curl --silent --show-error --list-only --user syncbot: --key ~/.ssh/id_ed25519 sftp://sftp.example.net/~/incoming/
   archive
   daily-export-2026-04.csv
   reports

   If the filename is missing, recheck the path first. SFTP paths are absolute unless /~/ is used deliberately.

5. Download the same remote file into a separate local filename so the first retrieval does not overwrite the source copy.

   $ curl --user syncbot: --key ~/.ssh/id_ed25519 --output ./daily-export-2026-04.download.csv sftp://sftp.example.net/~/incoming/daily-export-2026-04.csv
     % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                    Dload  Upload   Total   Spent    Left  Speed
   100    22  100    22    0     0    474      0 --:--:-- --:--:-- --:--:--   474

   --output overwrites an existing local file with the same name.

6. Inspect the downloaded file before handing the transfer off to the next job.

   $ cat ./daily-export-2026-04.download.csv
   job,status
   nightly,ok

   A quick content check catches wrong remote paths earlier than a later import, restore, or batch failure.