Exact by Expo: README promises vs first-week reports

The README of expo/exact opens with one big sentence: write an app once, run it natively on the web, macOS, iOS and Linux, and let an AI agent build it, run it, see it and test it on every one of them. Everything below that sentence is a commitment, so this piece checks the commitments against what GitHub shows and what people have actually written.

First, the README is upfront that Exact is pre-1.0, changes daily, and offers no API stability or migration guide. The dates fit that description. Its first day on GitHub was 2026-11-02, the newest push landed 2026-11-10, and across that short span this MIT-licensed Rust project gathered 1,642 stars.

On Hacker News, doodlesdev, 2026-11-09 reacted warmly, writing "This is absolutely huge." and added "If the Expo team can demonstrate that this development strategy is viable, we will finally see a resurgence of native applications and more efficient software, getting rid of the Electron bloat." The same comment ends with "It's a long shot for now, though!", so even the enthusiast treats the promise as unproven.

Next is the README's agent workflow. It tells the agent to run setup once, then drive the app on web, macOS and the iOS Simulator through one script. In a GitHub issue, nqh-packages, 2026-11-09 reported that after setup finished and the setup check said the SDK tools were ready, running the iOS build in a new app still failed while the Rust build compiled the zeroize crate for the iOS simulator target. Issue #4 is closed, with 3 comments. In another issue, sregg, 2026-11-09 said every macOS drive and test shows the app window over whatever the person is working in, without the app being activated or taking keyboard focus. Issue #7 is closed too, with 2 comments. Both reports involve platforms the README's agent prompt targets.

A third issue comes from someone using Exact beyond the demo. camchis, 2026-11-09 described porting an existing React Native app to Exact for Android and iOS together, running a patch against commit 94b8671 and pointing at gpu/src/lib.rs. The tagline names web, macOS, iOS and Linux, so an Android port is outside the four platforms it lists. That issue was closed after 2 comments.

The README also sets speed budgets, such as 100 ms to the first interactive frame, and reports its own agent test of about 57 minutes for a todo app. None of the four sources cited here measures either claim. All four are dated 2026-11-09, and they come from one forum and one issue tracker, so this is a thin sample of a repo with 20 open issues.

Nothing cited here mentions the Linux target. The three issues concern iOS, macOS and an Android-and-iOS port.