Stated on the website is that Mbed TLS aims to be "easy to understand, use, integrate and expand".

XySSL was created by the French "white hat hacker" Christophe Devine and was first released on November 1, 2006, under GNU GPL v2 and BSD licenses.

In 2008, Christophe Devine was no longer able to support XySSL and allowed Paul Bakker to create the official fork, named PolarSSL.

Because Mbed TLS is written in the C programming language, without external dependencies, it works on most operating systems and architectures.

Since version 1.3.0, it has abstraction layers for memory allocation and threading to the core "to support better integration with existing embedded operating systems".