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My generated wallpaper catalog hashed differently on every run — isolating five sources of nondeterminism
The same image folder refused to produce the same catalog.json twice. Directory enumeration order, JSON.stringify key reordering, collation, Unicode normalization, and async completion order — measured one at a time across 1,225 files until the output settled on a single hash.
What Renovate may bump in an Expo app, and what it must never touch
Turning on automated dependency updates in a Rork-generated app also hands Renovate the 123 packages Expo SDK 57 pins. Measured on 2026-07-30, six of them sit a full major version behind npm latest. Here is how to generate the ignore list from the SDK instead of maintaining it by hand.
The same wallpaper appeared twice in my catalog — measuring perceptual hash thresholds across 324 images
Four approaches to image catalog deduplication measured end to end: SHA-256, dHash, a hue signature, and a block signature. dHash alone scored 0.9% precision. Here is why perceptual hashes collapse on smooth images, and how the ground truth turned out to be the thing that was wrong.
Counting what prebuild --clean will erase before you upgrade to Expo SDK 57
A raw diff between two generated ios/ trees showed 649 changed lines; only 3 were real edits. How to count what prebuild --clean erases, and move it into a config plugin.
When to Raise Your Minimum iOS Version — Count Leftover Branches, Not User Percentages
Judging a minimum OS bump by usage share produces the same answer every year, so the decision never happens. Here is the annotation convention, the sweep script that counts how many iOS and Android branches each candidate floor would retire, and what to watch for 30 days after.
What Filtering Out Prerelease OS Devices Cost Me — Separating Telemetry Tracks Instead of Dropping Them
Filtering prerelease OS devices out of telemetry left me with no warning signs on GA day. Here is the rebuild: an os_track dimension, a remote GA baseline, split alert thresholds, and a release gate that separates blockers from fixes.
Collapsing Duplicate Requests Into One: A Reference-Counted Single-Flight Layer
When several components fire the same API call at launch, you get a burst of identical requests. Here is a single-flight layer that shares one in-flight promise instead: how to build the key that decides the folding, the trap of handing out a failed promise forever, the trap of one caller's abort cancelling everyone, and the test that keeps it all from regressing, with the real network numbers alongside.
Resolving App Config in Three Layers: Merging Defaults, User, and Remote With Bounded Overrides
A single type-safe layer that merges compiled defaults, user preferences, and remote config. So a broken remote value never takes your app down, each key gets its own override strength, plus schema validation and range clamping, built from a real production incident.
When Bumping Push to Three a Day Cut Next-Week Returns — Field Notes on Measuring Notification Frequency by D7 Retention and Opt-Out Rate
The assumption that heavier push means more returns was quietly eroding my D7 retention. These are field notes on re-measuring notification frequency by install-cohort D7 and opt-out rate, and walking from three a day back to one.
Handing Over an App — What an App Store Transfer Carries, and What You Rebuild
A practical look at App Store Connect app transfers when selling or moving an app: the eligibility criteria, what carries over (ratings, subscribers, iCloud data), what you rebuild (TestFlight, APNs, merchant IDs), and the three places users actually feel the change.
Sunsetting an App Well — Designing the Path from Update Freeze to Full Shutdown
What to do with an app whose revenue no longer covers its server bill. A three-stage decision table, a CDN-based sunset flag with TypeScript implementation, a data export path, and the practical order for winding down auto-renewable subscriptions.
When Rork Max's Two-Click Submit Stalls, Tell Which Layer Broke
Rork Max's one-click install and two-click submit fold the complexity of iOS shipping into four hidden layers. When the abstraction leaks and your submission stalls, this map helps you tell which layer failed and fix it yourself.