Jessie
Jessie has never been used as much as Jennie/Jenny, partly because it's a boys' name as well (spelled Jesse), but it does have a friendly and unpretentious, pioneer feel. In Scotland it's found as an Anglicized form of Teasagh, itself a form of Jean, and is used as a full name. And in the rest of the world, Jessie may be short for Jessica or used on its own.
Jessie
The "ie" version is usually for girls, with the simple e ending -- pronounced the same as Jessie -- for boys, though the spellings sometimes cross gender lines.
