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Voor SURFfilesender is een beknopte handleiding beschikbaar als PDF
(Nederlands- en Engelstalig).
A concise one-page manual for SURFfilesender is available as a PDF
(Dutch and English)

SURFfilesender logo.png

With SURFfilesender, you can safely transfer files containing sensitive data (encrypted if so desired). You can also use it simply to transfer large files. Recipients will receive a notification by e-mail and can then download the files from a secure server.

When to use SURFfilesender

Use cases

  • Transferring sensitive data
    When you need to transfer (documents containing) sensitive data, you should not send this information through regular e-mail. SURFfilesender optionally lets you encrypt files for additional security.
    For more information on sensitive data, visit the UU pages on privacy and information security.
  • Transferring large files
    SURFfilesender can be used as a safe replacement for services such as WeTransfer or Dropbox, to transfer files too large to be included in regular e-mail messages. Files up to 2GB may be encrypted for additional security.


  • Free for UU staff and students.
  • Dutch based server systems, in accordance with UU security regulations.
  • Maximum transfer file size is 500GB.
  • Optional encryption is end-to-end: files are encrypted before uploading and after downloading (client-side), passwords are never stored on SURFfilesender servers.
  • Sufficiently strong passwords can be generated by SURFfilesender.
  • Maximum encryption file size is 2GB.
  • Extensive notification options, ‘My Transfers’ dashboard.
  • SURFfilesender is available to associated institutions; users can send free vouchers to non-associated users, allowing them to upload files.
  • SURFfilesender servers are not backed up; once files are deleted from SURFfilesender servers, they cannot be retrieved.
  • SURFfilesender is browser operated; pre HTML5 browser types may have limited functionality, e.g. a maximum transfer file size of 2GB.

How to use SURFfilesender

Deze sectie is Engelstalig. Een beknopte handleiding is beschikbaar als PDF
(Nederlands- en Engelstalig).
This is a comprehensive manual. A concise one-page manual is available as a PDF
(Dutch and English)
  • Direct a web browser to the address
  • Click ‘Start transfer’ (or ‘Verstuur bestand’ when using the Dutch interface).
  • Below the welcoming message, click ‘Login’. If you see a list of institutions, select Utrecht University and use your UU credentials to login.
  • SURFfilesender screen.png
    In the SURFfilesender screen your UU e-mail address has already been entered, see the picture on the right (click to enlarge).

Minimal message

  • Click ‘Select files’ to select the files you want to transfer. If your browser allows this, you can also drag the files to the area marked ‘drag & drop…’.
  • Enter the recipients’ e-mail addresses in the ‘To’ field. These need not be UU addresses. Separate multiple addresses with commas or semi-colons.
  • In the ‘Subject’ field, enter the subject of the notification e-mail the recipient will receive.
  • In the ‘Message’ field, you can enter an extensive message to be shown in the notification e-mail.


Encryption is optional, but strongly advised for files containing sensitive data. Encryption is end-to-end, i.e. files are encrypted before they are uploaded, and decrypted after having been downloaded. Encryption is limited to files smaller than 2GB.

  • When ‘File Encryption’ is checked, the files will be encrypted with a password. Some extra options are shown:
    • In the ‘Password’ field, you can enter a password of your own choosing.
    • Or click ‘Generate password’ to generate a sufficiently strong password.
  • You must record the password yourself: it is not stored or shown in SURFfilesender!
    Recipients can only decrypt your files if they have the password.
    However, do not send the password within the SURFfilesender notification message: anyone with access to that message may then download and decrypt your files.
  • Use a different password for each transfer!
    If you transfer files to the same person(s) often, it may be tempting to use a fixed password for these transfers. Be very reticent about this, and when you do, use such a password only in transfers with the selected person(s).

Other options

On the right hand side of the SURFfilesender screen, you can set additional options, most of which speak for themselves.

  • You can set/change the expiry date, which is two weeks after upload by default. Note that files will be deleted irretrievably from the SURFfilesender server after the expiry date.
  • You can ask for a link to the uploaded file instead of sending a message. You can then send the link yourself. This may be handy when sending a file to large numbers of people, e.g. a mailing list. When encrypting files, do not send the encryption password with the link in the same message.

Upload / send notification

  • Check the box to accept the SURFfilesender Terms and Conditions.
  • Click ‘Send’.
  • Each recipient will receive a mail with download instructions.

‘My Transfers’

The ‘My Transfers’ button in the SURFfilesender toolbar will show the status of all your transfers. It allows you to see detailed information for each upload. Additionally, you can extend the expiry date, add recipients, send a reminder to recipients, or completely delete a transfer.

Guest vouchers

SURFfilesender is free for users from associated institutions. As an associated user, you can invite a non-associated user (the ‘guest’) to upload files. A voucher has an expiry date and can be used once by the guest to upload a set of files.
A guest’s upload is restricted to the inviting user by default, but this restriction can be lifted by deselecting the appropriate option.

The ‘Guests’ button in the SURFfilesender toolbar allows you to send vouchers. It offers an overview of outstanding invitations and their status regarding uploads.

See also