>As Duolingo’s products grow and evolve to reach even more learners around the world, Lottie animations help us keep users engaged, delighted, and always learning.[0]

>We thought the answer might lie in an alternative to a game engine —something that can help us take a limited number of assets and turn those into a virtually unlimited number of combinations. This is how we learned about Rive![1]

[0] https://lottiefiles.com/case-studies/duolingo

[1] https://blog.duolingo.com/world-character-visemes/

The animation of the walking bird is 246kB MP4. Bigger than Rive, sure, but it essentially takes no heap or runtime, which is at least 195kB of WASM.

The walking bird animation could probably be optimized much further through automatic decisions that the encoders can take.

You shouldn't use either Lottie or Rive for static animations.

I guess that depends on your use case. If you only have this animation on your website, then probably no. But if you load and run the rive engine anyway, because you build a game with it - then why not also use it for "static animations", if the result can be way sharper?

I mean, that fundamentally misses the point of vector graphics, no?

I could also argue that a screenshot of a rendered SVG icon takes no heap or runtime, which would also completely miss the point of why a designer would want vector icons. JPGs and MP4s alike are not infinitely scalable.

It’s tough. We’re chatting on a website with no graphics besides a low resolution letter Y logo. The most exciting UX development maybe ever in the history of computing is a chat interface. On mobile, it’s all scrolling through rectangles. It’s not looking good for the designers.

Only if you think that the job of a designer in the software industry is to add graphics.

By similar logic, the past hundred years have been bad for architects because there are no more stone gargoyles added to buildings.