Guide · OpenAI-compatible API · prices as of 23 October 2026

Switch the OpenAI SDK to open-weight models in three changes

If your code already calls OpenAI through its SDK, moving a workload to an open-weight model is a configuration change, not a rewrite. This guide shows the three values to change, which of our models to try for which job, and what behaves differently.

Last updated: October 23, 2026 · 4 min read

Quick answer

How do I use the OpenAI SDK with open-weight models?

Change three values: the base URL, the API key and the model name. With LLMwithCrypto, set the base URL to https://llmwithcrypto.com/api/v1, use a key from your dashboard and pick a model id such as deepseek-v4-pro or gpt-oss-120b. As of 23 October 2026, DeepSeek V4 Pro costs $1.254 per million input tokens. The rest of your code stays the same.

What are the three changes?

Base URL
Point the client at https://llmwithcrypto.com/api/v1 instead of OpenAI. Both the Python and the Node.js SDK accept a base_url / baseURL option, and read the OPENAI_BASE_URL environment variable.
API key
Create a key in your dashboard and keep it in LLMWITHCRYPTO_API_KEY. Pass your API key as a Bearer token in the Authorization header, as the OpenAI SDK does.
Model name
Replace gpt-… with one of our ids, for example deepseek-v4-pro. GET https://llmwithcrypto.com/api/v1/models lists every id your key can call.

switch.py

import os

from openai import OpenAI

client = OpenAI(
    base_url="https://llmwithcrypto.com/api/v1",
    api_key=os.environ["LLMWITHCRYPTO_API_KEY"],
)

reply = client.chat.completions.create(
    model="deepseek-v4-pro",
    messages=[{"role": "user", "content": "Summarise this changelog in three bullet points: ..."}],
)
print(reply.choices[0].message.content)
print(reply.usage)

switch.mjs

import OpenAI from 'openai';

const client = new OpenAI({
  baseURL: 'https://llmwithcrypto.com/api/v1',
  apiKey: process.env.LLMWITHCRYPTO_API_KEY,
});

const reply = await client.chat.completions.create({
  model: 'gpt-oss-120b',
  messages: [{ role: 'user', content: 'Write a regex that matches ISO 8601 dates.' }],
});
console.log(reply.choices[0].message.content);

Which open model should I try for which job?

A starting point by job, from what each model's maker built it for. Test on your own prompts before you switch: no model is a drop-in copy of another. Prices per 1M input / output tokens, as of 23 October 2026.

Job	Model to try	API id	Context	Price (in / out)
General chat, reasoning and code	DeepSeek V4 Pro	`deepseek-v4-pro`	1M	$1.254 / $3.762
High-volume, low-cost calls	DeepSeek V4.1 Flash	`deepseek-v4.1-flash`	1M	$0.285 / $1.14
Reasoning and tool use	gpt-oss-120b	`gpt-oss-120b`	128K	$0.142 / $0.57
Small, fast reasoning	gpt-oss-20b	`gpt-oss-20b`	128K	$0.033 / $0.161
Coding and agents	GLM-4.7	`glm-4.7`	200K	$0.57 / $2.09
Multilingual chat and long documents	Qwen3 235B A22B Instruct	`qwen3-235b-a22b-instruct-2507`	256K	$0.161 / $0.57
Step-by-step reasoning	DeepSeek R1	`deepseek-r1`	160K	$0.57 / $2.208
A European model	Mistral Large 3	`mistral-large-3`	256K	$0.475 / $1.424

Prices checked on October 23, 2026

The models page lists all twelve, with their licences.

What behaves differently after the switch?

Token counts. You pay per token from your balance: input and output tokens are counted by the model’s own tokenizer and charged at that model’s price per 1M tokens. A call that ends in an error costs nothing. Each model has its own tokenizer, so the same text can count as a different number of tokens than on OpenAI.
Features per model. Streaming works on every model; tool calling and JSON output follow what each model itself supports. Check the models page before you rely on tool calling or JSON output.
Output style and quality. Different models answer differently. Run your own test prompts, especially for structured output.
Closed-model features. OpenAI-only endpoints and models are not available here. We do not sell access to GPT, Claude, Gemini or Grok: their makers forbid reselling API access without their approval, and we do not have it.

Why do teams move workloads to open models?

Mostly for price and control. Open-weight models are served by many hosts, and the median price of DeepSeek V4 Pro across 7 hosts was $1.32 per million input tokens on 23 October 2026. Usage follows: in the week to 21 October 2026, DeepSeek V4.1 Flash was the most-used model on OpenRouter's public rankings.

With LLMwithCrypto you can also pay without a card: BTC, USDT, USDC, ETH, SOL, LTC, from a $25 top-up, with no KYC.

Switching from OpenAI: common questions

Does streaming still work?

Yes, with stream: true, as with OpenAI. The streaming docs show the event format.

Do I need a new SDK?

No. The official OpenAI SDKs work; only the base URL, the key and the model name change. LangChain works the same way, see the LangChain docs.

Can I keep GPT for some calls?

Yes, by keeping a second client pointed at OpenAI with your OpenAI key. We do not sell GPT models.

How do I check what a call cost?

Each response carries a usage object with input and output tokens; the dashboard shows the cost of every call, and GET https://llmwithcrypto.com/api/v1/credits returns what is left.

Sources (1)

OpenRouter rankings openrouter.ai/rankings — OpenRouter (read 2026-10-23)