demosthenes714

How much IP is captured at OpenAI though? Not to mention the hardware. I’m not super familiar with ML in practice but I have to imagine he would still be set back by a significant amount of time

John from the app team here, thanks for the question! I'd say most of the unexpected challenges came from building an app on top of a system that was primarily designed for emails and web. There's lots of tools in the publish email pipeline (queues, delays, retries, etc) that we don't really need to worry about with an app where we're directly querying for the posts for a user. Conversely there are functions like push notifications that apply to the app but not email. This led to plenty of refactors and some parallel backend code, although for the most part we were able to take advantage of the rest of the company's work.

Separately there's been some interesting challenges on the client side around caching posts, serving post content offline, and purging spam/copyright infringing content.

John from the app team here. We're currently respecting iOS font size settings, so if you increase that it will be reflected in the app. We have app specific font sizing on our roadmap though and it is coming soon!

John here, one of the iOS engineers. We're 100% UIKit but keeping a close eye on SwiftUI. It's certainly beautiful

John here, one of the app engineers at Substack. Our team has lots of experience with Swift and values the level of polish you can achieve natively, so went with that. We try to avoid third-party dependencies so native implementation and customization of UIKit, URLSession, and CoreData are important to us.

Cross platform frameworks like React Native, Flutter, Xamarin, etc are super interesting but in our experience can hold an app back long term. As you're able to dedicate more resources to the product, it's more likely that you'll want custom UI (animations, transitions, etc) and functionality that require full access to native APIs. It's a tough decision to make for early stage start-ups but we also went with native at Cocoon (our last startup which was acquired by Substack). I think some important factors that should go into the decision are 1) how important you think both Android and iOS support are out of the gate 2) how soon you'd expect to be able to hire native engineers for both platforms 3) your long term vision for the product and its desired complexity. We love Android (I've got some Kotlin experience myself) and will have it out ASAP, but with the existing email/web product there is less pressure for cross platform in our case.