engineering-paved-path

Guides development of Fastify Node.js backend servers and REST APIs using TypeScript or JavaScript. Use when building, configuring, or debugging a Fastify application — including defining routes, implementing plugins, setting up JSON Schema validation, handling errors, optimising performance, managing authentication, configuring CORS and security headers, integrating databases, working with WebSockets, and deploying to production. Covers the full Fastify request lifecycle (hooks, serialization, logging with Pino) and TypeScript integration via strip types. Trigger terms: Fastify, Node.js server, REST API, API routes, backend framework, fastify.config, server.ts, app.ts.

Next.js best practices - file conventions, RSC boundaries, data patterns, async APIs, metadata, error handling, route handlers, image/font optimization, bundling

Enforces Onion Architecture (dependencies point inward) on a TypeScript backend (a Fastify + Drizzle + Zod server/ package and a pure domain core, reviewer-core in the reference layout). Use this skill whenever you add or change a backend route, service, repository, adapter, DB query, contract, or DI wiring — and whenever deciding WHERE a piece of logic, an external-tool call (LLM/OpenAI/Anthropic/OpenRouter, GitHub/octokit, git, ripgrep/ast-grep, Postgres), a type, or a validation belongs across layers. Also use when reviewing layering, an import that crosses package/layer boundaries, a leaked Drizzle query, a directly-instantiated SDK client, or business logic creeping into a route. Trigger terms: onion architecture, layer, dependency direction/rule, ports and adapters, repository, service, adapter, composition root, container, dependency inversion, where should this live, layering violation.

Modern React best practices and anti-pattern catalog (2025-26). Use when writing, reviewing, or refactoring React components, hooks, and state management. Covers component design, state patterns, hooks misuse, performance, data fetching, and code organization.

React/Next.js frontend architecture & code organization (2025-26): where files live, how to split components, feature-based structure, co-location, constants/utils/helpers/types/hooks placement, where business logic goes, import boundaries, barrel files, path aliases, and naming conventions. Use when structuring a new frontend, deciding where a file or piece of logic belongs, splitting an oversized component/module, reviewing folder layout, or naming files. Stack-agnostic (React 19 + Next.js 15 App Router aware).