The Library

What changes once one machine becomes several — ordering, delivery, partial failure, and the patterns that keep a system honest when the network does not cooperate.

• Eventual vs Strong Consistency Explained 4 min
• Exactly-Once Semantics in Distributed Systems 4 min
• Idempotency Keys: Patterns and Pitfalls 3 min
• Kafka vs RabbitMQ: A Log Is Not a Queue 4 min
• The CAP Theorem: You Only Choose During a Partition 4 min
• The Circuit Breaker: Failing Fast So You Can Recover 4 min
• The Outbox Pattern: Commit and Publish Atomically 4 min
• The Saga Pattern: Transactions That Cannot Roll Back 4 min

Where state lives. Storage engines, indexes, memory models and the trade-offs behind every "it depends" answer you have ever been given.

• Cursor vs Offset Pagination: Why Page 5,000 Is Slow 4 min
• Database Connection Pooling, and Why Yours Is Exhausted 4 min
• Database Indexing: What the Index Actually Does 4 min
• Sharding vs Partitioning vs Replication 4 min
• The N+1 Query Problem: One Loop, Four Hundred Round Trips 4 min
• Transaction Isolation Levels Explained 4 min
• UUID vs Auto-Increment: Picking a Primary Key 4 min

Building systems on top of models that are non-deterministic, expensive and occasionally wrong — retrieval, evaluation, cost, identity and the guardrails that make any of it shippable.

• Caching LLM Calls Without Lying to Your Users 5 min
• Evals: Testing a System That Never Repeats Itself 5 min
• MCP: What the Model Context Protocol Actually Standardises 4 min
• Prompt Injection: Why Filtering the Input Cannot Work 5 min
• RAG vs Fine-Tuning: Knowledge or Behaviour 4 min
• What Your AI Agent Authenticates As 5 min

Proving who a request belongs to — sessions, tokens, OAuth, and the failure modes that turn a login form into a breach.

• Authentication in Web Apps — The Complete Guide 4 min
• How OAuth 2.0 Really Works 4 min
• JWT vs Session Authentication: Where the State Lives 5 min
• Refresh Token Rotation: Detecting Theft You Cannot Prevent 4 min

Trading freshness for speed on purpose — where to put a cache, what to evict, and how to invalidate without lying to your users.

• HTTP Caching Headers: Cache-Control and ETag 4 min
• Redis Internals in a Nutshell 5 min
• Redis vs Memcached: When the Simpler One Wins 4 min

Getting code from a laptop to production repeatedly and boringly — images, builds, pipelines and the caches that make them fast.

• Docker Layer Caching: Why Your Build Is Slow 3 min
• Mastering Docker Multi-stage Builds 4 min