[squarecog]

I was in charge of the Twitter data platform team at the time we developed Heron and deprecated Storm. The Mesos component of your retelling is not quite right. Take a look at this comment I wrote around the time we started talking about Heron, addressing the same misconception: https://news.ycombinator.com/item?id=10056479

[pixelmonkey]

Good context! I encourage others to read squarecog's linked comment.

[didibus]

Does Twitter now rely on Heron then or is there a new in-house replacement? Are some teams still using Storm?

[squarecog]

Now? No idea. At the time I left in 2016, all Storm usage was replaced by Heron, that was the point of making it API-compatible.