The One-Line OpenAI SDK Trick That Unlocks 16 AI Models (2026)

The OpenAI Python / Node / Go SDK has a feature that's changed how multi-model AI apps are built — but most tutorials don't cover it.

You can point it at any OpenAI-compatible endpoint just by changing base_url. Everything else — chat.completions.create, streaming, tool use, token counting — works identically.

This post shows the pattern, the gotchas, and how to use it to instantly access 16 AI models from one place.

The pattern (2 lines of code)

from openai import OpenAI

# Standard OpenAI — what you probably have:
client = OpenAI(api_key="sk-openai-xxx")
# → calls openai.com

# Point at AIPower — 16 models, same SDK:
client = OpenAI(
    base_url="https://api.aipower.me/v1",  # ← 1
    api_key="sk-aipower-xxx",              # ← 2
)
# → now you can call anthropic/claude-opus, deepseek/deepseek-chat, etc.

That's it. The rest of your code doesn't change.

What you can do with it

# Before (locked to OpenAI models)
r = client.chat.completions.create(model="gpt-5.4", ...)

# After (pick any model)
r = client.chat.completions.create(model="openai/gpt-5.4", ...)
r = client.chat.completions.create(model="anthropic/claude-opus", ...)
r = client.chat.completions.create(model="anthropic/claude-sonnet", ...)
r = client.chat.completions.create(model="google/gemini-2.5-pro", ...)
r = client.chat.completions.create(model="deepseek/deepseek-chat", ...)
r = client.chat.completions.create(model="qwen/qwen-plus", ...)
r = client.chat.completions.create(model="zhipu/glm-5.1", ...)
r = client.chat.completions.create(model="moonshot/kimi-k2.5", ...)
r = client.chat.completions.create(model="doubao/doubao-pro-256k", ...)
r = client.chat.completions.create(model="minimax/minimax-text-01", ...)

# Or use smart routing:
r = client.chat.completions.create(model="auto-cheap", ...)   # → Doubao Pro
r = client.chat.completions.create(model="auto-code", ...)    # → Claude Sonnet
r = client.chat.completions.create(model="auto-best", ...)    # → Claude Opus

Node.js is the same pattern

import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.aipower.me/v1",   // ← 1
  apiKey: process.env.AIPOWER_API_KEY,    // ← 2
});

const response = await client.chat.completions.create({
  model: "anthropic/claude-opus",
  messages: [{ role: "user", content: "Write a haiku about CSS" }],
});

Go + Curl work too

// Go — go-openai package
config := openai.DefaultConfig("sk-aipower-xxx")
config.BaseURL = "https://api.aipower.me/v1"
client := openai.NewClientWithConfig(config)

# Curl — nothing special, just different URL
curl https://api.aipower.me/v1/chat/completions \
  -H "Authorization: Bearer sk-aipower-xxx" \
  -H "Content-Type: application/json" \
  -d '{"model":"auto-code","messages":[{"role":"user","content":"..."}]}'

Gotchas

1. Model IDs are namespaced

OpenAI uses bare IDs (gpt-5.4). Gateways use provider/model namespacing (openai/gpt-5.4, anthropic/claude-opus). If you forget, you'll get 404 Model Not Found.

2. Streaming still works — but check chunk shape

Streaming SSE responses follow OpenAI's chunk format. Every gateway worth using preserves this. AIPower does, but always verify with a quick stream=True test on a new provider.

3. Tool use format

Claude's native tool-use format differs from OpenAI's. AIPower translates automatically so tools=[...] works as OpenAI expects. Some gateways don't — verify with a tool-use test if that's part of your workflow.

4. Token counting

Different providers tokenize slightly differently (Claude and GPT disagree on whitespace). Cost estimates based on tiktoken will be ~5-10% off for Claude / Gemini. Trust the server's usage field, not your local token counter.

5. Max tokens + context length

Each model has different limits. Claude Opus: 200k context / 16k output. GPT-5.4: 272k / 32k output. DeepSeek V3: 64k / 8k output. Use the right max_tokens for your model — setting 100k output on DeepSeek will error.

The real unlock: experimentation velocity

Before base_url swapping was common, swapping models meant rewriting API calls. Now you change one string and compare quality. Run the same prompt against 5 models, see which one's output you like best, pick one — in 15 minutes.

This is how production AI apps iterate now. If you're still hardcoded to one provider, you're leaving optimization on the table.

Try AIPower

16 models through one OpenAI SDK. 2 free trial calls on signup: aipower.me. +100 bonus on first $5 top-up. WeChat Pay + Alipay + card accepted.