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JOURNAL — ENGINEERING

Writing on AI & Engineering

Deep dives from the TwilightCore team into AI engineering, full-stack architecture, system design, and the technical decisions behind production systems.

12Articles
111+Min Reading
5Topics
Featured Article
Architecture
Code
Diagrams
Comparison
AI EngineeringFebruary 20, 202612 min read

Building Production RAG Systems That Actually Work

Most RAG tutorials show toy examples. Here's what it really takes — hybrid retrieval, eval-gated CI/CD, chunking strategies that survive messy documents, and the metrics that matter in production.

RAGLLMProductionpgvectorEvaluation
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2026
AI Engineering
Jan 15, 202610 min

Designing Multi-Agent Systems with LangGraph

How to architect agent supervision graphs, handle inter-agent communication, implement human-in-the-loop approval, and avoid the deadlock traps that plague multi-agent workflows.

ArchitectureDiagramsCode
LangGraphAgentsLLMArchitecture
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2025
Full Stack
Nov 10, 20259 min

Next.js Architecture Patterns for Large Applications

How to structure a Next.js 15 project that scales — App Router patterns, data layer separation, server/client component boundaries, and state management without the chaos.

ArchitectureCodeDiagrams
Next.jsReactTypeScriptArchitecture
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AI Engineering
Sep 18, 20258 min

Prompt Engineering Beyond the Basics

Chain-of-thought, few-shot calibration, structured outputs with PydanticAI, and the systematic evaluation framework we use to optimize prompts for production systems.

CodeComparisonTutorial
LLMPrompt EngineeringPydanticAIEvaluation
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AI Engineering
Jul 22, 202511 min

Vector Databases Compared: pgvector vs Pinecone vs Qdrant

A practical benchmark of three vector databases across latency, recall, cost, and operational complexity — tested with real production workloads, not synthetic benchmarks.

ComparisonDiagramsCode
Vector DBpgvectorPineconeBenchmarks
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System Design
May 14, 202510 min

Scaling WebSocket Connections to 100k Concurrent Users

The architecture behind our real-time trading dashboard — Redis Streams, connection pooling, backpressure handling, and the subtle bugs that only appear at scale.

ArchitectureDiagramsDeep Dive
WebSocketsRedisScalingReal-time
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Full Stack
Mar 10, 20257 min

Building Type-Safe APIs with tRPC and Next.js

End-to-end type safety from database to frontend — tRPC v11 setup, Zod validation, optimistic updates, and the patterns that eliminated an entire class of runtime errors.

CodeTutorial
tRPCTypeScriptNext.jsAPI Design
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DevTools
Jan 20, 20259 min

CI/CD for AI Applications: Beyond Traditional Testing

How to build deployment pipelines that test AI quality, not just code quality. Eval suites as pytest fixtures, accuracy gates, cost monitoring, and rollback strategies for model regressions.

ArchitectureCodeDiagrams
CI/CDAITestingDeepEval
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2024
AI Engineering
Dec 1, 202414 min

Fine-Tuning LLMs: When, Why, and How

A decision framework for when to fine-tune vs prompt engineer vs RAG. Includes dataset preparation, LoRA configuration, evaluation methodology, and cost analysis across model sizes.

Deep DiveComparisonCodeDiagrams
Fine-tuningLLMLoRATraining
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DevTools
Nov 15, 20246 min

Developer Tools That Actually Changed Our Workflow in 2024

A curated list of tools we adopted this year that made a measurable difference — from local LLM coding assistants to terminal workflows, database tools, and observability platforms.

ComparisonTutorial
ToolsProductivityDXReview
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Career
Oct 8, 20248 min

From Prototype to Production: What Nobody Tells You

The unglamorous work between "it works on my machine" and "it handles 10k users" — error budgets, observability, load testing, feature flags, and the mindset shift from builder to operator.

Deep Dive
ProductionEngineeringCareerBest Practices
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AI Engineering
Aug 25, 20247 min

Setting Up a Local LLM Development Environment

Our complete local AI development setup — Ollama model management, GPU memory optimization, VS Code integration, and benchmarking scripts to compare model performance on your own hardware.

TutorialCode
Local LLMOllamaDevelopmentSetup
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