openai/openai-python · error · ValueError

No embedding data received

Error message

No embedding data received

What it means

parse_embedding_response decodes base64 embeddings into numpy float arrays when no explicit encoding_format was requested. If the API response contains an empty data list, there is nothing to decode and it raises ValueError('No embedding data received').

Source

Thrown at src/openai/lib/_parsing/_embeddings.py:21

import array
import base64
from typing import cast

from ..._types import Omit, NotGiven
from ..._utils import is_given
from ..._extras import numpy as np, has_numpy
from ...types.create_embedding_response import CreateEmbeddingResponse


def parse_embedding_response(
    obj: CreateEmbeddingResponse, *, encoding_format: str | Omit | NotGiven
) -> CreateEmbeddingResponse:
    if is_given(encoding_format):
        # don't modify the response object if a user explicitly asked for a format
        return obj

    if not obj.data:
        raise ValueError("No embedding data received")

    for embedding in obj.data:
        data = cast(object, embedding.embedding)
        if not isinstance(data, str):
            continue
        if not has_numpy():
            # use array for base64 optimisation
            embedding.embedding = array.array("f", base64.b64decode(data)).tolist()
        else:
            embedding.embedding = np.frombuffer(  # type: ignore[no-untyped-call]
                base64.b64decode(data), dtype="float32"
            ).tolist()

    return obj

View on GitHub (pinned to 9917c6e28e)

Solutions

  1. Inspect the raw response before parsing (check len(response.data))
  2. Retry the embeddings.create call — an empty body is usually transient or a proxy issue
  3. If you requested base64 explicitly, pass encoding_format='base64' so the helper returns the response untouched

Example fix

# before
parsed = parse_embedding_response(response, encoding_format=NOT_GIVEN)
# after
if not response.data:
    raise ValueError("empty embedding response from API")
parsed = parse_embedding_response(response, encoding_format=NOT_GIVEN)
Defensive patterns

Strategy: validation

Validate before calling

if not response.data:
    raise ValueError("empty embedding response; retrying")

Try / catch

try:
    parsed = parse_embedding_response(response, encoding_format=NOT_GIVEN)
except ValueError as e:
    if "No embedding data" in str(e):
        response = client.embeddings.create(...)  # retry
    else:
        raise

Prevention

When it happens

Trigger: A CreateEmbeddingResponse arrives with data == [] (or the mock/response object has no data) and encoding_format was not given, when using the embeddings parsing helper.

Common situations: Mocking responses without data; a malformed or truncated API response; proxy/gateway stripping the body.

Related errors

AI-assisted analysis of openai/openai-python@9917c6e28e (2026-08-28). Data as JSON: /api/errors/21c26c3b3cfaa329. Report an issue: GitHub.