egemma2: EmbeddingGemma 2 in Rust, for Python

An open-source, from-scratch Rust implementation of Google's EmbeddingGemma 2: text, images, audio and video embedded into one 768-d space (Matryoshka cuts to 512 / 256 / 128), on the CPU or an NVIDIA GPU. This package installs the egemma2 binary plus a small Python client that keeps it loaded, so Python code gets the speed without PyTorch:

Embeddings match the PyTorch reference: up to 1e-6 apart in float32, and within cosine 0.99996 in bf16 mode. Texts are not truncated, as in sentence-transformers.

Install

pip install "egemma2[hub]"     # with huggingface_hub, to download the model on first use (~1.5 GB, once)
pip install egemma2            # or just the binary and the client, for a model you already have

Wheels: Windows and Linux x64, any Python 3.8+. The GPU path needs an NVIDIA driver and the CUDA 13 runtime libraries (cuBLAS, NVRTC) on PATH, for example from the CUDA Toolkit; bf16 needs compute capability 8.0+ (Ampere or newer). Without them egemma2 runs on the CPU.

Use

from pathlib import Path
from egemma2 import Egemma2

with Egemma2(precision="bf16") as model:            # device="auto": CUDA if available, else the CPU
    docs = model.embed(["Mars is red.", "Oceans are blue."], prompt_name="Document")
    query = model.embed("which planet is red?", prompt_name="SearchQuery")[0]
    scores = [sum(q * d for q, d in zip(query, doc)) for doc in docs]   # cosine similarity

    pages = model.embed([Path("page1.png"), Path("page2.png")])          # files, by extension
    mixed = model.embed([{"text": "Figure 3:", "image": pil_image}])     # one interleaved input
    matrix = model.embed_numpy(texts, dimensions=256)                    # (n, 256) float32

• Inputs: a str is text, a Path is a file (image, .wav audio, video file or frame directory). Images can also be Pillow images, HxWx3 uint8 numpy arrays or encoded bytes; audio can be (samples, sample_rate). A dict such as {"text": ..., "image": ...} is one input whose parts follow the dict's order, like sentence-transformers' dict inputs.
• Prompts: prompt_name takes the model's sentence-transformers prompts (SearchQuery, Document, QuestionAnswering, CodeRetrieval, ...).
• Model directory: Egemma2(model_dir=...), else $EGEMMA2_MODEL_DIR, else ./models/embeddinggemma-2, else a download of google/embeddinggemma-2 via huggingface_hub.
• Other options: device="cpu" | "cuda" | "cuda:N", precision=None | "tf32" | "bf16", max_tokens=N to cut long texts.

The client starts egemma2 serve once and sends it JSON lines, so the model loads once; a short query takes 2.6 ms round trip. Requests from several threads are queued safely.

Command line and HTTP server

The same install gives you the egemma2 command (also python -m egemma2):

egemma2 --model-dir <dir> embed --prompt-name SearchQuery --text "which planet is red?"
egemma2 --model-dir <dir> --bf16 serve --http 127.0.0.1:8080     # OpenAI-compatible /v1/embeddings

Any OpenAI-style client (the openai SDK, LangChain, LlamaIndex) can use the HTTP server:

from openai import OpenAI
client = OpenAI(base_url="http://127.0.0.1:8080/v1", api_key="unused")
r = client.embeddings.create(model="embeddinggemma-2", input=["a document"], extra_body={"prompt_name": "Document"})

More

Documentation, benchmarks, the parity tests and the source: https://github.com/Dalailalama/embeddinggemma2-rust. Not affiliated with or endorsed by Google; the model weights are Google's (Apache-2.0). Code: Apache-2.0. If it saves you time, you can buy me a coffee.