The site is built with Ghost[0] and subscriptions are managed by Outpost[1].
Design is clean, loads fast, and articles are stacked, so I wish them luck. It's pretty ruthless out there, but a few good stories on HN front-page[2] should at least get this syndicated in all the best places.
[0]: https://ghost.org/ (they've also forgotten to change the default article:publisher URL which leads to Ghost's FB page)
[1]: https://outpost.pub/