LangChain

LangChain is a framework for applications that use language models. Create its OpenAI chat model with the exchange as the base URL. Use the same base URL and key for embeddings.

Before you start

• A workspace with a balance and a spend key. See API keys.

1. Export the key

export LIQUID_API_KEY=sk-liquid-...

2. Install the package

# Python 3.10 or later
pip install langchain-openai

3. Send a request

Create the OpenAI chat model with the exchange as its base URL. The X-Title header names the client on your receipts.

import os
from langchain_openai import ChatOpenAI

llm = ChatOpenAI(
    base_url="https://router.inference.ai.exchange/v1",
    api_key=os.environ["LIQUID_API_KEY"],
    model="liquid.auto",
    default_headers={"X-Title": "LangChain"},
)

To get the current model names, use GET /v1/models. See Market data.

Embeddings

Use OpenAIEmbeddings with the same base URL and key to buy vectors. See Embeddings.

import os
from langchain_openai import OpenAIEmbeddings

embeddings = OpenAIEmbeddings(
    model="text-embedding-3-small",
    base_url="https://router.inference.ai.exchange/v1",
    api_key=os.environ["LIQUID_API_KEY"],
    check_embedding_ctx_length=False,
)

vectors = embeddings.embed_documents(["a cat on a bicycle", "a dog in a car"])

Set check_embedding_ctx_length=False.

• If it is True, the class splits each text into tokens and sends arrays of token numbers. The exchange does not support token arrays and refuses the request.
• With False, the class sends the text.

Pass this embeddings object to a vector store such as QdrantVectorStore or PGVector. See Qdrant and pgvector.

Notes

• The exchange sets a cap on each request. It is in the x-liquid-cap-usd response header. To limit total spend, set a spending limit on the key. See API keys.
• To send purchasing rules, pass an exchange block in extra_body. See Purchasing rules.

Troubleshooting

See Errors for the error codes.

Next steps

• LiteLLM: a Python library with one interface to many APIs.
• OpenAI SDK: streams and purchasing rules in code.
• Purchasing rules: models, strategy and limits, and presets.