Securely send files with the web service FileSender

More and more colleges and universities worldwide offer their students and staff the opportunity to send large research files via their own infrastructure. They do this via the web service FileSender, which they can host in their own ICT environment. FileSender can be downloaded free of charge and also offers possibilities for secure file exchange.

Organisations can manage FileSender entirely at their own discretion. After downloading code on GitHub, they are free to choose where to store their users’ files. They can do that in their own data center, but they can also store data with a public cloud service such as Amazon. Organizations that offer FileSender as a service and don’t want the exchange of data to take place abroad then choose cloud storage in their own country.

AES 256 encryption

FileSender provides security when exchanging files. Users choose the file encryption option. Within the browser, the computer encrypts the files the user wants to share. For the encryption FileSender uses the AES 256 encryption. Recipients can access the files by means of a password chosen by the sender.

If the users choose to send encrypted data, the files are of course also encrypted on the server. The organization behind FileSender does not have access to the files in any way. The key is only in the possession of the sender and receiver of the files. With other web services with which users can exchange files, it happens that the key is stored on the server of the service. This is a less secure solution. FileSender has solved this better with end-to-end encryption.

Of course, the administrator must also properly secure the server on which FileSender is installed. An administrator must take measures to ensure that the server is not compromised by malicious parties. The administrators themselves are responsible for the security of the server on which FileSender is installed. The organization behind FileSender has no influence on this.


The secure exchange of data via FileSender can be done up to a maximum file size of 2 GB. This limitation is due to technical limitations when encrypting and decrypting data in a browser. The developers involved in FileSender are working on a way to remove this limitation so that it is also possible to send larger files with encryption.

Without security it is possible to send files larger than 2 GB with FileSender. With similar web services, users face file size limitations. This has to do with built-in limits in internet browsers. With FileSender they have solved this problem and recently they managed to send files with a size of 600 GB.

FileSender development team

About 10 people are currently working on the development of FileSender. In addition, FileSender administrators also provide input for improvements. They sometimes find bugs and then inform the FileSender development team about them. It ensures a continuous improvement of FileSender.

If you want to install and offer FileSender, you can download the free code on GitHub. The code can be used and improved by anyone. When administrators sign up for the administrator list, they’ll automatically be notified by email when they can download a new version of FileSender. This way, administrators are always able to offer the latest version of FileSender with all its features and improvements to their users.

FileSender can be used via SURFfilesender, for example. In order to send files, however, you must be connected to an institution that collaborates with SURFNet in relation to FileSender. Via the “Send Voucher” button you can share a file with someone who does not have access to FileSender.