Galaxy is an open web-based platform for biomedical research. It offers a lot of tools for the data analysis and allows to build multi-step data processing workflow. Galaxy supports data upload from the user's computer, and from online resources.
Galaxy is available in following ways:
As a free public web server.
As open-source software that can be downloaded and installed for the local usage.
Several organizations with their own Galaxy installation have also opted to make those servers available to others. List of such public or semi-public Galaxy servers can be found here.
Note that using the public Galaxy servers you should register and upload your file prior to use its tools. It can take a lot of time depends on how busy it is with other people's work.