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Semantic (vector) search captures meaning; keyword (BM25) search captures exact terms. Hybrid search blends both with one parameter, alpha, so you can tune relevance per query or per index. As with all queries, load the index first (or open a session).

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The alpha parameter

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Choosing alpha

  • Lower alpha (toward keyword) when queries contain exact identifiers, SKUs, names, or jargon.
  • Higher alpha (toward semantic) when queries are natural-language paraphrases.
  • Tune per index and per intent (returns, billing, onboarding, etc.).

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What the score means

The returned score is a relevance value, not the sort key: results stay in hybrid order. A pure keyword query (alpha=0) scores every hit 0. See Score semantics for exactly what it means, how to threshold with min_score, and the SDK version it needs.

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Implementation

Runnable, per-language examples live in the SDK guides:

Metadata filtering

Constrain results by document metadata.

Custom embeddings

Bring your own vectors.