Learn LLM Path / pillar 3 of 10
Free track: every swapped resource costs $0. Concepts you already checked stay checked.
build RAG that works in production. Biggest hidden gap - basic tutorials stop at "embed + top-k," real systems need hybrid search, reranking, evaluation
3a · Foundations
Why RAG; embeddings; vector DB; cosine KEY
RAG from First Principles - Ankit Bansal (YouTube)videoFREE38m
Build a real RAG app
LangChain: Chat with Your Data - DeepLearning.AIvideoFREE~1.5h
3b · Advanced retrieval (the gap)
Hybrid search: BM25 + dense + RRF
Production RAG w/ LangChain & Vector DBs - freeCodeCampvideoFREE7h38m
Reranking (cross-encoders/ColBERT)
Advanced RAG techniques - Field Guide to AIarticleFREE9m read
Query transforms (HyDE, multi-query)
Advanced RAG: hybrid, reranking, query expansion (read)articleFREEread
Chunking: parent-child, sentence-window
12 Advanced RAG Techniques (2026) - AtlanarticleFREEread
GraphRAG / RAPTOR / Contextual Retrieval
Same Atlan guide (techniques 8-12)articleFREEread
3c · RAG evaluation (RAGAS) [KEY]
Metrics: faithfulness, context precision/recall
RAG Evaluation, RAGAS explained - Logical LensesvideoFREE12m
RAGAS hands-on in Python
RAG Evaluation Metrics Tutorial - Analytics VidhyavideoFREE6m
Free · 4b · Advanced retrieval (the gap most courses skip)
Advanced RAG applications, end-to-end
Building and Evaluating Advanced RAG Applications - DeepLearning.AIvideo~1.5h⚠ link unverified