The HitFilm product line provides you with several workflow options so that you can integrate HitFilm technology into your projects.
HitFilm
The core HitFilm software is standalone and requires no additional software. It includes an editor, a powerful compositor with a unified 3D workspace and over 500 effects. Switching between the editor and your visual effects shots is as easy as changing tabs in your web browser. Two variants are available: HitFilm Express, which is free, and HitFilm Pro.
Academy Award-winning planar tracking is provided by Mocha HitFilm, a special version of Mocha from Boris FX. 3D Objects from Boris FX is also included, for advanced 3D titles. 
You can import 3D objects into HitFilm Pro and create sophisticated particle effects without requiring additional 3rd party plugins. This functionality is also available in HitFilm Express, through the purchase of the 3D: Model Render add-on pack.
OpenFX
HitFilm Pro is OpenFX compliant. This means you can add additional functionality to the software from other plugin developers such as GenArts, NewBlue FX, Red Giant and RE:Vision. OpenFX is a Pro Exclusive feature, and is not available in HitFilm Express.
Compatible OpenFX plugins that are installed on your system will appear in the Effects panel alongside the standard HitFilm effects library.
Find out more about HitFilm Pro’s OpenFX compliancy here.
Ignite Pro
If you are already have an established workflow built around a third party editor, there is an option for accessing HitFilm Effects as plugins within select third party NLEs. Ignite Pro is a collections of HitFilm effects, which supports Adobe Premiere Pro, Adobe After Effects, Apple Final Cut Pro X, Apple Motion, Vegas Pro, Sony Catalyst Edit, DaVinci Resolve, Foundry NUKE, Grass Valley EDIUS, and Avid Media Composer.
The Ignite Pro plugins mirror many of the effects inside HitFilm Pro itself. This means you can choose whether to work with HitFilm technology inside HitFilm Pro or your established editor.
Find out more about Ignite Pro here.
Vegas Integration
HitFilm Pro includes direct integration with the latest version of Vegas Pro. If you are editing in Vegas, you can send a video clip to HitFilm for further compositing or effects work, then move back to Vegas without rendering. The HitFilm project is placed on the Vegas timeline, where it can be edited like other media clips. This integration ensures optimum quality by eliminating the need to render the scene repeatedly, which could introduce generational quality loss.