While developing on RESTful and Oauth protected APIs I had often the need to make raw http requests to the server. Because there was no application -as far as I know- wich was capable of making raw http requests wich can be easily modified (except telnet) I started this project. The first commit was on 2010-06-16 under the project name "oat". After using this tool for ca. 1 year I decided to change the name to aletheia and start an open-source project because it is maybe useful for other users.
You can use this application for debugging and finding security issues in web applications. Because it is possible to modify every bit of the request it is easy to exploit web applications. That means you can set i.e. costum cookies user agents or send file uploads to the server. You can even send corrupted http requests to see how the server responds. This application also helps to understand how the http protocol works.