Move from the OpenAI API

The exchange serves Chat Completions and a stateless part of Responses. Most OpenAI code changes in two places: the base URL and the API key. Model names, and features that need OpenAI to keep state, need more work. For setup, see OpenAI SDK.

Change these three things

1. Issue a spend key on the API keys page. See API keys.
2. Set the base URL to https://router.inference.ai.exchange/v1 (or OPENAI_BASE_URL). Send the key as Authorization: Bearer sk-liquid-… (or OPENAI_API_KEY).
3. Change each model to a name that GET /v1/models lists. See Model names.

Then check these:

• Remove each parameter that the exchange refuses. See OpenAI features.
• Run a dry run. See Check a request without a purchase.
• Read What is different about money. The exchange never lowers an output limit that you set. See Output limits.

What differs

• Model names. An unknown name, or a fine-tuned model, returns 404 model_not_found.
• n greater than 1. Refused. OpenAI bills every choice, and the exchange serves one.
• State in Responses. previous_response_id, conversation and background: true are refused. Send the full conversation in input.
• Hosted tools. The exchange runs none. It removes web_search with the header x-liquid-notice: web_search_dropped and refuses the others. To search the web, add :web (beta) to the model name.
• Not available. The Batch, Files, Assistants and Moderations APIs, and image edits.
• Retries. The SDK retries a 5xx response, and each try is a new request. To get the first response again, send the same idempotency-key header. See Purchasing rules.

With with_raw_response, the SDK returns the headers, including x-liquid-cap-usd.

Example

An OpenAI request, then the same request for the exchange. The new request changes the client and the model, removes n=2 (refused) and store and service_tier (ignored), and adds a cap and a data rule. user stays, because it names the end user for guardrail limits. The model name is an illustration.

from openai import OpenAI

client = OpenAI()

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Say hello."}],
    max_completion_tokens=500,
    n=2,
    store=True,
    service_tier="auto",
    user="user-123",
)

import os
from openai import OpenAI

client = OpenAI(
    base_url="https://router.inference.ai.exchange/v1",
    api_key=os.environ["LIQUID_API_KEY"],
)

response = client.chat.completions.create(
    model="gpt-oss-120b",
    messages=[{"role": "user", "content": "Say hello."}],
    max_completion_tokens=500,
    user="user-123",
    extra_body={"exchange": {"cap_usd": 0.05, "privacy": {"retention": "none"}}},
)

Reference

Model names

Send a name that GET /v1/models returns. The model field accepts a model, a router model, a basket or a preset. See Model names. The exchange never uses a different model.

max_completion_tokens, max_tokens and max_output_tokens (Responses) are all accepted. Reasoning tokens count toward the limit.

OpenAI features

Troubleshooting

For 402 insufficient_balance and 400 no_eligible_offer with param set to exchange.cap_usd, see What is different about money.