There are two forms of licenses available for TypeIt — an open source license, a limited commercial license, and an unlimited commercial license.
An open source license exists as GPLv3, and permits you to use TypeIt in any open source or personal project. Along with many other details, the GPLv3 license requires that any publicly released code using TypeIt be licensed under the GPLv3 as well.
A limited commercial license permits you to use TypeIt in any single commercial product or application. It doesn’t live under any of the requirements of the GPLv3, and also doesn’t require you to license your code in any particular way. It’s yours with which you can do what you want.
An unlimited commercial license is identical to the limited commercial license, with one key difference — you can use TypeIt for any number of commercial projects. For example, if you’re a freelancer whose confident that TypeIt would be valuable for any number of future contracts, this is the license for you.