Toward a Universal App Architecture

In his AI Speaker Series presentation at Sutter Hill Ventures, Evan Bacon presented his work on ExpoRouter and DirectFlight, tools designed to address the challenges in mobile app development and distribution. Here's my notes from his talk:

90% of time spent on mobile devices occurring inside native apps, particularly in regions outside America where mobile-first adoption is highest
Despite this, desktop and web platforms remain favored for high-performance tasks, though AI is rapidly enabling more productive mobile experiences for complex tasks like video editing and data analysis
While people are increasingly on mobile, getting native software int he app stores on these devices is still difficult for developers

ExpoRouter & Server Components


ExpoRouter is the first file-based framework that enables building both native apps and websites from a single codebase
By creating files in the app directory, developers automatically generate navigation systems that work across native and web environments
This leverages familiar web APIs like Link and Ahrefs for navigation, making the system intuitive for web developers
This combination of web-like development with native rendering has driven widespread adoption, with approximately one-third of content-driven apps in the iOS App Store (across shopping, business, sports, and food/drink categories) now using React Native and Expo
ExpoRouter's file-based architecture means every screen in an app automatically becomes linkable on both web and native platforms.
The system extends to advanced features like app clips, where URLs to websites can instantly open native content, downloading just what's needed on demand.
React Server Components represent the next evolution in this approach, enabling ExpoRouter apps to use the same data fetching and rendering strategies employed by best-in-class native applications
These components are serialized to a standardized React format that functions like HTML for any environment, creating a consistent system across platforms
The architecture supports streaming content delivery, allowing apps to start rendering on the client while the server continues creating elements and fetching data so apps look and feel identical to native apps


Deploying to App Stores

Even with improved development tools, getting apps to users remains complex, requiring Xcode (Mac-only), code signing, encryption status declarations, and a $100 developer fee
Expo addresses part of this challenge by enabling website deployment worldwide with a single command (EAS deploy), bringing modern web deployment practices to cross-platform development
But App Store distribution still requires Apple's multi-layered review processes
To address these distribution challenges, Bacon created DirectFlight, a tool that automates the process of adding testers to TestFlight
DirectFlight creates self-service links that allow users to add themselves to a development team and download apps without developer intervention for each user
This eliminates the need for developers to manually navigate Apple's slow interface, fill out redundant information, and manage the invitation process
DirectFlight works within Apple's rules by automating the official steps rather than circumventing them, making it a sustainable solution
There's lots of AI-powered tools for making native apps from text prompts. But these tools need streamlined distribution, which DirectFlight could help with.
As these tools mature, they promise to allow more developers to reach users directly with native experiences rather than being limited to web platforms