Every Experiment Kept Landing on the Same Devices: Hash Choice and Salt Position, Measured Across a Million IDs
On-device experiment assignment looked fine in isolation, then collapsed the moment two experiments ran side by side. Here is what one million IDs revealed about four hash functions, why the culprit was the concatenation order rather than hash quality, and the implementation I settled on, with the measured numbers.
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.
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 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.
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.
Shipping Notifications Without Asking First — Provisional Authorization in Rork Apps, and the Expo Snippet That Quietly Undoes It
iOS lets you start delivering notifications with no permission dialog at all, via provisional authorization. The catch: expo-notifications reports granted as false for provisional devices, so the registration snippet in Expo's own docs re-requests permission and fires the very dialog you were avoiding. Here's why granted lies, a hook that models authorization as five states, how to write notifications for quiet delivery, when to ask for the upgrade, and how to keep provisional out of your CTR.
The Three-Minute Video That Kept Failing — Moving Rork's Gemini Uploads Off the Worker
How I rerouted video uploads to the Gemini Files API from a Cloudflare Workers relay to a direct device-to-Google path — why the 128MB isolate limit breaks the relay, how to hand out a resumable upload URL without leaking your API key, and how resolution and frame rate actually decide the bill.
The Update That Failed Because a Profile Expired Three Months Ago
Apple signing assets expire quietly and nothing tells you. Here is how to count the days left with the App Store Connect API and put the audit on a weekly Cloudflare Workers cron.