Reported News
Expo's Exact: a cross-platform app runtime built for AI agents to build, run and test
Exact, an MIT-licensed project in Expo's GitHub organization created on Nov 2, 2026, says it lets you "Write an app once" and run it natively on the web, macOS, iOS and Linux. Agents drive every host through ten operations; the README says it is pre-1.0 and "changes daily."
- Changes reported
- 6
- listed below, each from a source we read
- We tested
- Not tested yet
- reported from sources; we did not run it ourselves
- Gaps we flag
- 4
- things we could not verify
- Sources
- 1
- 1 primary, linked below
What changed
| # | What the source says | Status |
|---|---|---|
| 01 | Exact is a cross-platform runtime: the interface is written in Contract, a small declarative language, and data logic in TypeScript or Rust. The compiler turns the interface into a plan that runs on the web over a roughly 20 KB runtime driving the real DOM. | Reported |
| 02 | On macOS, iOS and Linux a Rust runner executes the same plan with a Rust layout kernel using CSS rules, drawing with AppKit, UIKit or a GPU painter. The README says there is no webview and no JavaScript bridge in the UI. | Reported |
| 03 | Agents get ten operations that work the same on every host (tree, screenshot, tap, type, state, layout, logs, clock, prefer, perf) through one script, scripts/agent.mjs. The README notes the predecessor's agent API had grown to eighty wire names. | Reported |
| 04 | The agent controls the clock: nothing moves between operations, so tests advance time with commands like clock +60000 instead of sleeping. An app.test.contract test file runs unchanged on any host. | Reported |
| 05 | The README's tracked budgets include 100 ms p50 cold start to first interactive frame and 100 ms p50 edit-to-present dev restart. It reports a fresh agent built a tested to-do list app on three platforms in about 57 minutes in an Oct 4 run. | Reported |
| 06 | Status: pre-1.0 with no API stability, backwards compatibility or migration guide by design. The repo had 2,361 GitHub stars when we checked, nine days after it was created. | Reported |
reported by the sourcemeasured or run by usnot verified
Primary source: GitHub: expo/exact README. We are the fast, independent index; the vendor’s own page is the source of record for this release.
In the source’s words
“There is no webview and no JavaScript bridge in the UI, and no app JavaScript runs before the first pixel.”
What we have not verified
- We did not build or run an Exact app; performance budgets and the 57-minute agent run are the README's own claims.
- The README does not state that Exact is an official Expo product or give a roadmap; we only confirmed the repository sits in the expo GitHub organization.
- Android and Windows support are not described in the parts of the README we read.
- The star count is a snapshot from the GitHub API on Nov 11, 2026.
This brief is Reported: written from the sources below, not from running the release ourselves.
Sources
- GitHub: expo/exact READMEprimary source · fetched 2026-11-11
Related
Spotted an error? See our corrections policy or email the address on the contact page. Markdown version for agents: /news/expo-exact-agent-native-cross-platform-runtime.md
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