Legal restrictions on importing other file formats?

[Alpha-Snail]

I've developed a professional application that has many great features.

One addition that I would like to add is the ability to import sales leads from various lead source companies. Since each file format is in a sense "proprietary" to each company, am I legally obligated to gain their approval before scripting a solution that I provide to others?

[The Shadow]

This is called reverse engineering if you just figure out their format on your own (or with Google's help)

Reverse Engineering