Modern TypeScript/JavaScript testing with Vitest. Fast unit and integration tests, native ESM support, Vite-powered HMR, and comprehensive mocking. Use for testing TS/JS projects.

React and Next.js performance optimization guidelines from Vercel Engineering. This skill should be used when writing, reviewing, or refactoring React/Next.js code to ensure optimal performance patterns. Triggers on tasks involving React components, Next.js pages, data fetching, bundle optimization, or performance improvements.

Use for Docker with Bun, Dockerfiles, oven/bun image, containerization, and deployments.

SEO optimization with keyword analysis, readability assessment, technical validation, content quality. Use for search rankings, blog posts, content audits, or encountering keyword density, readability scores, meta tags, schema markup errors.

Optimizes API performance through payload reduction, caching strategies, and compression techniques. Use when improving API response times, reducing bandwidth usage, or implementing efficient caching.

Use when integrating Drizzle ORM with Bun's SQLite driver for type-safe schema definitions and migrations.

Use for Bun runtime, bunfig.toml, watch/hot modes, env vars, CLI flags, and module resolution.

Systematically trace bugs backward through call stack to find original trigger. Use when errors occur deep in execution and you need to trace back to find the original trigger.

Implements multi-language support using i18next, gettext, or Intl API with translation workflows and RTL support. Use when building multilingual applications, handling date/currency formatting, or supporting right-to-left languages.

Multi-language Workers development with Rust, Python, and WebAssembly. Use when building Workers in languages other than JavaScript/TypeScript, or when integrating WASM modules for performance-critical code.

Build MCP (Model Context Protocol) servers on Cloudflare Workers with tools, resources, and prompts.

TypeScript-first schema validation and type inference. Use for validating API requests/responses, form data, env vars, configs, defining type-safe schemas with runtime validation, transforming data, generating JSON Schema for OpenAPI/AI, or encountering missing validation errors, type inference issues, validation error handling problems. Zero dependencies (2kb gzipped).

Bun package manager commands (install, add, remove, update), workspaces, lockfiles, npm/yarn/pnpm migration. Use for dependency management with Bun.

Configures API gateways for routing, authentication, rate limiting, and request transformation in microservice architectures. Use when setting up Kong, Nginx, AWS API Gateway, or Traefik for centralized API management.

Designs RESTful APIs with proper resource naming, HTTP methods, status codes, and response formats. Use when building new APIs, establishing API conventions, or designing developer-friendly interfaces.

Review WooCommerce code changes for coding standards compliance. Use when reviewing code locally, performing automated PR reviews, or checking code quality in WooCommerce projects.

Database sharding for PostgreSQL/MySQL with hash/range/directory strategies. Use for horizontal scaling, multi-tenant isolation, billions of records, or encountering wrong shard keys, hotspots, cross-shard transactions, rebalancing issues.

Implements real-time WebSocket communication with connection management, room-based messaging, and horizontal scaling. Use when building chat systems, live notifications, collaborative tools, or real-time dashboards.

Comprehensive Cloudflare account management for deploying Workers, KV Storage, R2, Pages, DNS, and Routes. Use when deploying cloudflare services, managing worker containers, configuring KV/R2 storage, or setting up DNS/routing. Requires CLOUDFLARE_API_KEY in .env and Bun runtime with dependencies installed.

Complete CI/CD guide for Cloudflare Workers using GitHub Actions and GitLab CI. Use for automated testing, deployment pipelines, preview environments, secrets management, or encountering deployment failures, workflow errors, environment configuration issues.