No, not really. (It depends.) What does “slow” mean? I said it before, and I will say it again: If you didn’t measure it, it is not slow, and even if you measure it, the numbers are meaningless without context. That being said, the fact that people will not even consider adopting Web Workers because of their concerns about the performance of postMessage(), means that this is worth investigating. M
![Is postMessage slow? — surma.dev](https://cdn-ak-scissors.b.st-hatena.com/image/square/cdda22b8c67437dd3bb90980941498a2121ed824/height=288;version=1;width=512/https%3A%2F%2Fsurma.dev%2Fthings%2Fis-postmessage-slow%2Fsocial.png)