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Field reports from production, written for engineers who want the failure modes included.

July 10, 20263 min read

Building a Production PWA: What the Tutorials Don't Tell You

Lessons from shipping nihongojouzu.jp: service worker update traps, Web Push on iOS, offline-first state, and why the PWA parts were harder than the app parts.

PWANext.jsService WorkersWeb Push

July 2, 20263 min read

15 Years in Software: The Lessons That Survived

From a loan system in the Philippines to marketplace and insurance platforms serving millions in Japan. The principles that kept being true across every stack and country.

CareerEngineering CultureLessons

June 8, 20263 min read

AI-Assisted Development, Six Months In: An Honest Workflow

What actually changed after introducing AI review into my PR workflow and building with Claude daily as a sole engineer. Where it multiplies a senior engineer, where it lies, and the discipline that makes it safe.

AIDeveloper ToolsCode ReviewClaude

May 18, 20263 min read

How I Cut Our Infrastructure Bill by 80%

A systematic teardown of a startup's cloud spend: the leaked API key worth ¥100k/month, the caching that replaced compute, and treating the bill as telemetry.

InfrastructureCost OptimizationDevOps

March 22, 20263 min read

Migrating APIs Under Traffic: Lessons from a Marketplace Serving Millions

Moving PHP and GraphQL systems to Java REST while millions of users kept shopping. Strangler patterns, latency budgets, and why the 30% win came from boring decisions.

APIsJavaMigrationScale