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---
title: "OpenAITextEmbedder"
id: openaitextembedder
slug: "/openaitextembedder"
description: "OpenAITextEmbedder transforms a string into a vector that captures its semantics using an OpenAI embedding model."
---
# OpenAITextEmbedder
OpenAITextEmbedder transforms a string into a vector that captures its semantics using an OpenAI embedding model.
When you perform embedding retrieval, you use this component to transform your query into a vector. Then, the embedding Retriever looks for similar or relevant documents.
| | |
| --- | --- |
| **Most common position in a pipeline** | Before an embedding [Retriever](../retrievers.mdx) in a query/RAG pipeline |
| **Mandatory init variables** | "api_key": An OpenAI API key. Can be set with `OPENAI_API_KEY` env var. |
| **Mandatory run variables** | "text": A string |
| **Output variables** | "embedding": A list of float numbers <br /> <br />"meta": A dictionary of metadata |
| **API reference** | [Embedders](/reference/embedders-api) |
| **GitHub link** | https://github.com/deepset-ai/haystack/blob/main/haystack/components/embedders/openai_text_embedder.py |
## Overview
To see the list of compatible OpenAI embedding models, head over to OpenAI [documentation](https://platform.openai.com/docs/guides/embeddings/embedding-models). The default model for `OpenAITextEmbedder` is `text-embedding-ada-002`. You can specify another model with the `model` parameter when initializing this component.
Use `OpenAITextEmbedder` to embed a simple string (such as a query) into a vector. For embedding lists of documents, use the [OpenAIDocumentEmbedder](/docs/openaidocumentembedder), which enriches the document with the computed embedding, also known as vector.
The component uses an `OPENAI_API_KEY` environment variable by default. Otherwise, you can pass an API key at initialization with `api_key`:
```python
embedder = OpenAITextEmbedder(api_key=Secret.from_token("<your-api-key>"))
```
## Usage
### On its own
Here is how you can use the component on its own:
```python
from haystack.components.embedders import OpenAITextEmbedder
text_to_embed = "I love pizza!"
text_embedder = OpenAITextEmbedder(api_key=Secret.from_token("<your-api-key>"))
print(text_embedder.run(text_to_embed))
## {'embedding': [0.017020374536514282, -0.023255806416273117, ...],
## 'meta': {'model': 'text-embedding-ada-002-v2',
## 'usage': {'prompt_tokens': 4, 'total_tokens': 4}}}
```
:::note
We recommend setting OPENAI_API_KEY as an environment variable instead of setting it as a parameter.
:::
### In a pipeline
```python
from haystack import Document
from haystack import Pipeline
from haystack.document_stores.in_memory import InMemoryDocumentStore
from haystack.components.embedders import OpenAITextEmbedder, OpenAIDocumentEmbedder
from haystack.components.retrievers.in_memory import InMemoryEmbeddingRetriever
document_store = InMemoryDocumentStore(embedding_similarity_function="cosine")
documents = [Document(content="My name is Wolfgang and I live in Berlin"),
Document(content="I saw a black horse running"),
Document(content="Germany has many big cities")]
document_embedder = OpenAIDocumentEmbedder()
documents_with_embeddings = document_embedder.run(documents)['documents']
document_store.write_documents(documents_with_embeddings)
query_pipeline = Pipeline()
query_pipeline.add_component("text_embedder", OpenAITextEmbedder())
query_pipeline.add_component("retriever", InMemoryEmbeddingRetriever(document_store=document_store))
query_pipeline.connect("text_embedder.embedding", "retriever.query_embedding")
query = "Who lives in Berlin?"
result = query_pipeline.run({"text_embedder":{"text": query}})
print(result['retriever']['documents'][0])
## Document(id=..., mimetype: 'text/plain',
## text: 'My name is Wolfgang and I live in Berlin')
```