He is joking. Don't take it seriously.

他是跟你开玩笑呢。你别当真。

《新英汉大辞典》

Chapter 6 is about infinite streams; I couldn't finish it, it just went on and on (okay, joking!).

第6章是有关无限数据流的问题；我们不能结束这个数据流，它只会无限制地继续下去(开玩笑)。

youdao

I'm not at all joking, your mind is the most powerful tool you have, it has the power to make things and break things.

我真的不是在开玩笑。你的信念是你所拥有的最好的工具。

youdao

It's a very funny poem, and you've got triplet rhymes there to make sure you know that Frost is joking, and it feels like light verse.

这是首有趣的诗，你会得到三连音的押韵,让你确实觉得弗罗斯特在开玩笑，这就像光的韵律一样。

耶鲁公开课 - 现代诗歌课程节选

It is tempting to think that he is joking, and that his theoretical elaborations about the true significance of communist-era jokes are a subtle parody of the way that modern literary critics so often miss the point of the texts they write about.

ECONOMIST: Communist jokes

At the Supreme Court, the only half-joking saying is it's Justice Kennedy's America and the rest of us are just living in it.

NPR: The Supreme Court Shifts Direction

He is joking, but it is hard to tell.

BBC: Malta going for Eurovision gold