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.
- bundleUnavailable: Silent Bundle Drop Read as 'No Discount'
- signed_terms_source_version Unchecked, Terms Shown as Agreed
- gcloud sql clone point-in-time: a Real Restore Drill
- enabled: false Silently Disabled Claude Code Scheduled Tasks
- maxOutputTokens Was Missing, So Usage Had No Ceiling
- 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
- A Poster's Title Shows Up as IMG_1234 on the Classroom TV
- Bing Webmaster UrlCount Stuck at 1: the sitemap-index Trap
- listTotal Skips the units Multiplier, Preview Price Drifts
- max-width:900px Loses to a Later Same-Specificity Rule
- ScanFilter.setDeviceAddress Throws on the String "null"
- migrate_image_tag drifts from live after concurrent deploys
- dpm set-device-owner Launches the App Before prefs Is Set
- gcloud ADC Expires After ~44h: Reauthentication failed Fix
- allUsers + objectViewer on GCS Grants list, Not Just get
- Valid Token, Wrong Scope: an IDOR via design/date Parameters
- vercel inspect won't show which commit is live
- term_months Display Drifts From Amount After Term Extension
- @media(max-width:899px) Leaks Into a Scaled Signage Preview
- semgrep --config=auto Turns main Red, No Code Changed
- amount_unset: Stripe's 7-Day Auto-Switch Never Fires
- sp.units Query Param Shows 5x Price for a 1-Unit Invite
- gen-og.ts Cache Hid an Overwritten OG Image on 91 Posts
- Next.js 15.1.6 Got Blocked by Vercel as a Vulnerable Version
- pnpm-lock.yaml Made Vercel Misdetect an npm Project as pnpm
- Next.js Server Action Fail-Open: error Read as Success
- 01.dnsv.jp Full-Zone Replace Deletes Unrelated A Records
- console_name.sql Collided Again 58 Minutes Later