funnel
A funnel with every screen logged, and no idea where users left
Screen tracking was firing, yet the funnel question stayed unanswerable. The data landed where I could not query it, and one step I added would read 100% forever.
kiniinsight
What actually happened when I built it, including the wrong guesses.
Notes from building mobile apps - the parts that broke, what the fix actually was, and the tools behind it. Written from what I ran, not from memory.
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August 24, 2026Earlier
22 postsgit
One line changed and git recorded 295
When line endings flip from LF to CRLF, git treats every line as modified. Measured numbers for the diff, the blame damage, and why -w beats --ignore-rev.
subscriptions
Wiring subscriptions: a full Play Store checklist
Every step of attaching subscriptions to an Android app, in order, with the specific places it silently breaks and how to tell which layer failed.
in-app subscriptions
Most of the work in shipping in-app subscriptions was not code
Wiring in-app subscriptions blocked three releases in one day. Every blocker was a name or a scope that had to match across two systems, and none of them errored.
LLM
What makes an LLM call cacheable is not temperature
Caching an LLM call looked trivial until I checked why it was safe. The reason I reached for first was wrong, and partial hits corrupted the totals.
design tokens
The design tokens existed. The code just did not use them
An app with design tokens still had 953 hardcoded colors, and 349 of them were values the tokens already defined. Automating the swap went wrong twice.
uniq
uniq Says Two Different Korean Lines Are Duplicates
On macOS, uniq reports duplicates that do not exist in non-Latin text. It collapsed 397 distinct lines into one. The cause is collation, and uniq never signals it.
morning routine
What people searching for morning routines actually ask about
I measured 40 morning routine autocomplete suggestions. Eight ask about side effects and failure, and the real question underneath is whether sleeping less is fine.
Android
Android widgets: a working preview does not mean a working widget
I shipped the same broken Android widget four times. The preview looked right and the build passed, but adding it to the home screen failed every time.
habits
People who keep breaking habits are already counting the tries
I measured 36 autocomplete suggestions for a Korean phrase about broken habits. Three ask how to fix it. Five assume it already happened again.
search intent
Four of my five keywords died on search intent
I picked five topics by search volume and dropped four an hour later. Reading the ranking pages showed the search intent behind those words was different.
typescript
My TypeScript check was silent, not passing
I judged TypeScript by grepping tsc output for a string it never prints. It stayed silent every time, and I read silence as success. Six real errors were hiding.
study planner
Searching for a study planner returns three different things
The phrase study planner returns a consultant, a paper notebook, and an app in one page of results. Decide which you want, or you buy whichever had the best ad.
firestore index
The Firestore index deployed and the error stayed
I deployed a Firestore index, relaunched, and got the identical failed-precondition error. The deploy was fine. A building index reports exactly like a missing one.
entry point
Turning off the auto popup removed the only entry point
I disabled a bottom sheet that opened automatically because it annoyed me. That automatic open was its only entry point. I did the same thing twice in two days.
voice input
I added voice input for todos because planning was tedious
Typing todos into my own app annoyed me, so I built voice input for one spoken sentence. No model, just regex, and a split rule that nearly cut verbs in half.
react-native
The JS ran at 60fps and the screen stayed black
A 3D planet stopped animating on iPhone only. The GL context was alive, three.js rendered every frame, and endFrameEXP fired 60 times a second. Nothing reached the screen. The cause was React Native's view flattening.
CLAUDE.md
Your CLAUDE.md rules disappear on the next machine
Instruction files fail open. Auditing CLAUDE.md turned up two rules living only on this laptop, plus two referenced files that never existed.
GLB file size
GLB file size: 99% of mine was textures the app threw away
Two sky models arrived at 8MB for a phone app. Almost all of that GLB file size was 2048px textures my renderer discards before the first frame.
habit streaks
Habit streaks punish the people who are best at them
Habit streaks get heavier the longer they run: one missed day costs 3 early on and 100 later. Here is what I shipped instead, with numbers.
react native modal
A React Native Modal always wins: the new-user soft lock
The onboarding button did nothing and the app looked frozen. A React Native Modal is a separate window, so it swallows touches from everything below.
scheduled notifications
Scheduled notifications outlive the account that created them
After a sign-out, the previous user's tasks kept firing on my lock screen. Scheduled notifications live in a per-device OS queue that auth state never touches.
turborepo
Turborepo said cache hit and restored nothing
Turborepo reported FULL TURBO in 62ms and wrote zero build artifacts. The cause was one line in outputs, sitting behind a root task that had not run for 71 days.