Guides
From “what is a reranker?” to hybrid retrieval pipelines and evaluation — pick a starting point or read straight through.
What is a reranker?
Two-stage retrieval, why order matters, when reranking pays off.
Cross-encoder vs bi-encoder
Speed vs accuracy — and why production stacks use both.
How to add reranking to RAG
Retrieve wide, rerank tight — with Python, LangChain, and latency tips.
Hybrid retrieval + rerank
Combine BM25 and vector search, then let the reranker fix the merge.
How to evaluate rerankers
NDCG, MRR, labelled queries, and regression tests for your domain.
Self-host a reranker
sentence-transformers, GPU sizing, and a minimal FastAPI service.
Choose by scenario
RAG vs support vs legal vs code — which model fits your use case.
Late-interaction (ColBERT)
When ColBERT beats bi-encoders and when you still need cross-encoder rerank.
Instruction-following rerank
Task instructions that change what “relevant” means — vs plain cross-encoders.
Live in-browser demo
Watch a cross-encoder reorder passages — bi-encoder proxy included.