Knowledge Index — 지식 지도

Why REST still dominates, what GraphQL actually solves, and when gRPC really shines. A practical breakdown of all three API protocols with real code and decision criteria.

Kubernetes looks overwhelming at first glance. This post breaks down what Pods, ReplicaSets, Deployments, Services, Ingress, ConfigMaps, and Secrets actually do and how they connect — with practical YAML examples and local dev setup.

Converting words and sentences into numeric vectors lets you do math on meaning. From cosine similarity and ANN algorithms to the OpenAI embeddings API, here's everything you need to know.

Once you ship a public API, you can't change it freely. Compare four versioning strategies for evolving APIs without breaking clients, plus analysis of real-world choices by GitHub, Stripe, and Twilio.

100% code coverage but bugs still slip through? Having tests doesn't mean having good tests. Here's how mutation testing reveals the real quality of your test suite.

Public APIs face unexpected traffic floods without proper protection. Rate limiting, API key management, and IP restrictions to protect your API.

Started with admin/user roles but requirements grew complex. When RBAC isn't enough, ABAC provides attribute-based fine-grained control.

With 3 services needing separate logins, SSO unified authentication. One login grants access to everything.

Password resets were half my support tickets. Passkeys eliminate passwords entirely, but implementation is more complex than expected.

SQLite is just for mobile apps? Turso and Litestream made it a serious option for production web services with edge replication.

Adding a column to a production table locked it for 5 minutes. Learning zero-downtime migration strategies the hard way.

You don't always need Elasticsearch. PostgreSQL's built-in Full-Text Search handles most search needs without extra infrastructure.

Beyond basic SELECT: JSONB, CTEs, and Window Functions dramatically expand what you can do in a single SQL query.

I only used Redis as a cache until I discovered it handles sessions, leaderboards, pub/sub, and rate limiting. It's a Swiss Army knife.

Solo developers can't get code reviews? AI review tools changed that. Setting up automated code review on every PR.

My first LLM API integration brought token cost explosions, latency issues, and hallucinations. Here's what I learned building real features.

MCP lets AI read files, query databases, and call APIs through a standardized protocol. Think of it as USB for AI tool connections.

ChatGPT answers questions. AI Agents plan, use tools, and complete tasks autonomously. Understanding this difference changes how you build with AI.

Asking AI to 'make a login page' gives garbage. Structured prompts with context, constraints, and examples produce production-ready code.

I actually used all three AI coding tools for real projects. Here's an honest comparison of Copilot, Claude Code, and Cursor.