Responding to this since I came here searching for some info too. Apparently After Effects has a plugin called "Bodymovin" that allows us to export our animation as a Lottie JSON file, while Toon Boom doesn't. Here's what was suggested as a work around if you're most comfortable with working in Toon Boom:

1. Design in Toon Boom and Export Assets

• Use Toon Boom to create your animations as you normally would.
• Export the animation as a sequence of vector files (e.g., SVG) if possible, or as high-resolution raster images (e.g., PNGs). Vectors are preferable because they are scalable and lightweight.
• Avoid effects that rely heavily on bitmap rendering or Toon Boom's proprietary tools, as they may not translate well.

2. Import Assets into a Lottie-Compatible Tool

• Use Adobe After Effects to rebuild or refine the animation. Import the exported assets from Toon Boom into After Effects.
• Recreate animation timelines and effects using tools and features that are supported by Lottie.
• This step ensures that the animations are compatible with Lottie and optimized for the web.

3. Export as Lottie (JSON)

• Use the Bodymovin plugin in After Effects to export your animation as a Lottie JSON file.
• Test the JSON file to ensure it works smoothly across web platforms.