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LLM Engineering

LLM Engineering is the discipline of shipping production systems built on large language models — covering RAG architecture, fine-tuning strategies, model evaluation, and the practical tradeoffs that determine what gets deployed versus what stays in a notebook. These articles cover the technical decisions that matter when you move from prototype to production.

RAG Fine-Tuning LLM Architecture OpenAI Production AI

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Frequently Asked Questions

What is LLM Engineering?

LLM Engineering is the practice of building production systems with large language models. It covers model selection, prompt design, RAG architecture, fine-tuning strategies, evaluation pipelines, and inference optimization — the full technical stack between a raw model and a working AI product.

What is the difference between RAG and fine-tuning for LLMs?

RAG (Retrieval-Augmented Generation) fetches relevant context at inference time from an external knowledge base, making it ideal for dynamic or frequently-updated information. Fine-tuning adjusts model weights for specific tasks or communication styles and is better for consistent behavior and lower-latency responses. Most production systems combine both: fine-tuning for style and RAG for knowledge.

How have GPT-5 models changed production LLM engineering?

GPT-5.3 introduced significantly fewer refusals and better instruction following, reducing prompt engineering overhead. GPT-5.4 added expanded context windows and improved agentic tool use, making it easier to build reliable multi-step pipelines without complex fallback logic.

When should I consider running LLMs locally?

Local LLMs make sense for private codebases, high-volume batch tasks where API costs add up, offline workflows, and experimentation without usage limits. Models like Qwen3-Coder are viable for coding assistance on modern hardware. The tradeoff is quality: frontier models still outperform local alternatives on complex reasoning tasks.