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A beta-SDK build can reach TestFlight, but it can't reach review
Builds made with a beta Xcode can be distributed through TestFlight, but they cannot be submitted for App Store review. Here is how to check which SDK produced your build, and how to protect your release profile in eas.json.
Three conditions that make Play Policy Insights report nothing on an Expo project
Google Play now ships an open-source policy auditing skill. Running it against an Expo-shaped project, one directory argument moved the result from five detected data categories to zero. Here is when the scan actually reaches your code, and where its output should not be trusted.
Version code 1 has already been used — who owns that number, app.json or EAS?
When a Play upload stops on versionCode, check where the number actually lives before bumping it. A one-command way to tell whether app.json, EAS, or build.gradle wins.
When an Expo UI drop-in swap actually removes a dependency
Expo UI went stable in SDK 56 with drop-in replacements for eight community packages. Swapping one import does not always shrink your dependency list. Here is how to decide which swaps actually pay off, straight from the dependency graph.
Find the Code That Trips App Store 2.5.2 Before You Submit
If a remote value can change what your app does, Guideline 2.5.2 may apply. Here is where the line actually sits, plus a script that surfaces the risky paths in your repo before submission.
Find the native edits expo prebuild will erase before you upgrade to SDK 57
Expo SDK 57 makes expo prebuild clear and regenerate ios and android by default. Here is how to audit your hand edits first, move them into config plugins, and why 57.0.9 matters for Reanimated apps.
Your lockfile's dev/prod split won't tell you which licenses your app must credit
A record of classifying every dependency in a production project to decide what belongs on an app's license screen, and where the copyleft findings and the actual shipped artifact turned out to disagree.
Switching to Signed URLs Killed My Image Cache — Decoupling expo-image Keys from the URL
Signed URLs rewrite their query string on every expiry, so a URL-keyed cache never hits. Here is how to pin the key with source.cacheKey, what the cache read and write APIs actually return, and what changed when I re-ran the measurements.
Measuring Hermes Bytecode Delta Updates: One Added Module Cost 29x More Than One Changed Line
I measured OTA delta sizes against a 2.4MB Hermes bytecode bundle. Changing one line cost 2,104 bytes; adding one module cost 61,197. The widely repeated advice about stable module IDs turned out to matter least.
The 429s Kept Coming After Recovery: Measuring Retry Jitter Across 2,000 Clients
My backend came back but the 429s did not stop. I rebuilt the scenario in a 2,000-client discrete simulator and measured what plain exponential backoff, delay caps, 10% jitter, and honoring Retry-After cost in seconds — then reran everything with server capacity that degrades under load.
Exactly 20 Characters, Still Rejected: Putting Character Counting Behind One Boundary
Emoji and combining marks make your client and your server disagree about length. I measured four counting methods on Node v22 and found 75.6% of naive truncations split a grapheme and 36.1% produced replacement characters over UTF-8. Here is the shared-module design that fixed it.
When Two-Character Queries Silently Return Nothing: Measuring Japanese Search Indexes in an Expo App
SQLite FTS5's trigram tokenizer returns zero rows for Japanese queries shorter than three characters, without raising anything. I benchmarked linear scan, a bigram inverted index, and FTS5 over a 20,000-item catalog to find the real threshold.