Just because the author of this piece seems to be looking at this post, some minor nitpicks regarding spelling/phrasing:

> GCS has native JSON API which more powerful

Missing a verb.

> OpenDAL needs to implement features in zero cost way which means:

"in a zero cost way" is probably better.

> What OpenDAL does?

What does OpenDAL do?

> Free to zero cost

This is a tricky one, right now it sounds a bit weird because you're turning 'to zero cost' into a verb, suggesting users would have to 'zero cost' things themselves. The problem is that 'free' and 'at zero cost' mean the same thing, so it's hard to use both in the same phrase. Free of cost could work.