Tech Blog
Engineering Blog
Written by the people who actually run these systems in production. Every article records what broke, why, and how it was fixed — down to the file and line the claim came from. Published in both English and Japanese.
- DETECTED/NOT_DETECTED: SwitchBot Webhooks Double-Count
- RLS PERMISSIVE Policies OR Together, Admin Policy Wins
- SecurityException Kills HDMI-CEC Power Control on Sideloads
- reconcilePayment Never Checks Amount, Marks Contracts Paid
- company_id Survives Contract End, Owner Check Isn't Enough
- AbortSignal.timeout Shorter Than the Server's Own Timeout
- size container Missing: cqh Falls Back to Viewport, Not Off
- userId From Request Body Overwrites Unrelated User Profile
- email_exists on createUser Hides a Silent Signup Failure
- share_links.kind Lacked 'receipt': a Feature Vanished
- durationSec 300s Cap Missed at Input, Fails as Permanent 400
- DeliveryAd Missing title Field Left Every Ad Untitled
- TS2307: a Test Importing scripts/ Broke the Vercel Build
- snapshotSignedPolicies Guard Blocks Contract Resign
- new row violates check constraint on documents.source
- Stripe fallbackToInvoice counted an unsent email as issued
- is_pinned=false Can't Exclude Specials, Only Pins
- Bundle Application Partial Failure Not Communicated to User
- valid_from Gap Retires Future-Dated Creatives
- signed_terms_source_version Unchecked, Terms Shown as Agreed
- gcloud sql clone point-in-time: a Real Restore Drill
- session cookie Stays Stale After Firebase TOTP Enroll
- enabled: false Silently Disabled Claude Code Scheduled Tasks
- Cloud Run Rate Limit Per-Instance Not Shared
- company_id Is Always Null on Public/Share Links
- Only Our Vercel API Functions Threw Cannot Find Module
- is_pilot Backfill Misses Companies With Only One EXISTS
- Filename Auto-Generated Title: IMG, DSC, Screenshot Excluded
- Bing Webmaster UrlCount Stuck at 1: the sitemap-index Trap
- listTotal Skips the units Multiplier, Preview Price Drifts