I scanned 23 open‑source Expo apps before they hit the App Store. Here’s what a pre‑flight check caught.

Description and use

Expo developers frequently encounter build failures and App Store rejections due to configuration errors. The author created the expo‑preflight CLI, which statically analyzes configuration files and identifies 13 real issues across 23 popular repositories, reducing false positives from 83 to 29.

Problem

Expo builds and store reviews often fail due to configuration errors that are hard to detect manually.

Outcome

The tool reduced reported errors from 83 to 29 after fixes, uncovered 13 real configuration problems, and demonstrated the value of automated cross‑file consistency checks.

Workflow

• Clone each repository
• Run npx expo-preflight
• Review the generated report
• Fix identified issues
• Re‑run the tool to confirm resolution

Evidence

I built a small CLI to do it, and then pointed it at real apps to see whether the problems are real.

Source

It reads app.json / app.config.*, package.json, eas.json and .gitignore, never runs your app and never prints secret values.

Source

My first run produced 36 errors and 56 warnings, and roughly half were wrong.

Source

Missing iOS usage strings (4 of the 6 apps with expo-image-picker or expo-media-library installed).

Source

A tracked .env in git (2 of 23 apps).

Source

Update channels that don't exist (2 of the 6 apps with both expo-updates and an eas.json).

Source