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Self-HostingBeginner20 minVerified 21 days ago

Run EmbeddingGemma 2 locally for text search

Sentence Transformers quick start from the model card. One pip install, two prompt names, and a similarity call. No token price because the weights are local.

embeddingsentence-transformerslocalretrievalon-device
What you get

A local embedding model at google/embeddinggemma-2 that can score a query against a document. The card's quick start is text. Images and audio are a later step, and they cost extra memory. Start with text.

The launch blog is October 6, 2026. The commands below are copied from the model card, not from a secondary tutorial.

Prerequisites
  • Python with pip
  • Enough RAM for the text stack. The card's text-only size is 270M parameters if you disable the other encoders. This recipe loads the default checkpoint. See the text-only recipe if RAM is tight.
  • No API key. There is no token price on the card.
Install
pip install -U sentence-transformers transformers
Encode a query and a document
from sentence_transformers import SentenceTransformer

model = SentenceTransformer("google/embeddinggemma-2")

query = "What causes the northern lights?"
document = "The northern lights are caused by charged particles from the sun."

query_emb = model.encode(query, prompt_name="SearchQuery")
doc_emb = model.encode(document, prompt_name="Document")
print(model.similarity(query_emb, doc_emb))

SearchQuery applies task: search result | query: {query}. prompt_name="Document" applies title: none. If the document has a real title, do not use that prompt name. Format it yourself:

doc_emb = model.encode(f"title: {title} | text: {document}")

Prefixes are for text. The card says to pass images, video, and audio with no prefix.

Checks before you trust a score
  • Query and document embeddings must use the same dimension. The native size is 768.
  • A search query prefix on both sides is the wrong setup. Retrieval is asymmetric: query prefix on the query, document format on the corpus.
  • Classification, clustering, and similarity are symmetric. The card's prompt names for those are Classification, Clustering, and SentenceSimilarity. Do not reuse SearchQuery for them.

Recipe verified 2026-10-07. Commands are tested but your environment may differ.

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