Category
型安全・バリデーション（TypeScript / Zod）の実践ガイド
型安全は「方針」で終わらせず、コンパイラとCIで強制してこそ価値が出ます。tsconfigの厳格化、any/as/enumの排除、境界でのZodによる parse、NeverErrorでの網羅性、ブランド型、E2Eの型一致、モノレポの型カバレッジ——不正な状態を表現不能にし、チームが速く変更し続けても壊れない規律を扱います。
5 articles in total
Foundational guide
Foundational guide (start here)
Production TypeScript Type-Safety Discipline: Banning any, Guarding Boundaries with Zod, and Forcing Exhaustiveness with NeverError
A practical guide to not letting type safety end as a 'policy.' Explained with real production code: strict-family tsconfig, banning any/as/enum, SSoT design parsing the boundary with Zod, forcing exhaustiveness with NeverError, satisfies, branded types, and type coverage in CI.
Related practical articles
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Designing a Type-Safe Monorepo with pnpm + Turborepo: Kill Drift with catalog, Make the Shared Domain Type the Single Source of Truth
An implementation guide to designing a production TypeScript monorepo with pnpm workspaces + Turborepo. Explained with real code: pinning dependency versions with catalog, turbo.json's task pipeline and caching, making the Zod shared-domain package the single source of truth, CI-enforcing type coverage, and detecting schema drift.
22 min read - TypeScriptフロントエンドアーキテクチャ設計Next.jsセキュリティ
TypeScript type-level programming in practice [2026 edition] — erase illegal states with types and support production quality
A complete guide that explains TypeScript's type-level programming narrowed to the range that 'works in practice.' With real code it shows practical techniques to eliminate illegal states with types while keeping readability and compile speed — discriminated unions and exhaustiveness checking (NeverError), satisfies, branded types, template literal types, mapped types, conditional types, NoInfer, and type testing.
9 min read - TypeScriptZodバリデーション型安全Next.js
Zod 4 Practical Guide [Latest 2026] — TypeScript Type-Safe Schema Validation, Boundary Validation, React Hook Form / Environment Variables / JSON Schema Integration
A practical guide faithful to the latest official documentation (Zod 4 / zod@4.x). From top-level string formats (z.email etc.), the unified error parameter, treeifyError/prettifyError/flattenError, z.toJSONSchema, metadata, to Zod Mini—it explains 'when, where, and how to use' with production-quality code examples. Also covers applications to React Hook Form, environment variables, API boundaries, and LLM structured output.
20 min read - Next.jsTypeScriptGoOpenAPIアーキテクチャ設計
Implementing 'End-to-End Type Safety' with Next.js 16 × Go × OpenAPI: The Complete Practice of Contract-First Architecture
A contract-first architecture connecting a Next.js 16 App Router and a Go backend with OpenAPI 3.1, guaranteeing client⇄server consistency at build time. Explained at production-operation level, all the way through Problem Details, Full Jitter backoff, the Circuit Breaker, OpenTelemetry propagation, and infrastructure definition with Terraform.
27 min read