Get Started with NixAPI in 5 Minutes: Zero-friction Access to GPT-4o and Claude

NixAPI is an LLM API relay service that is 100% compatible with the OpenAI API format. All you need to do is replace one line — base_url — and you can start using GPT-4o, Claude 3.5 Sonnet, and other leading models in your existing project at a lower cost.

This guide walks you through from registration to your first API call — about 5 minutes end-to-end.

---

Step 1: Register and Get an API Key

1. Visit nixapi.com and create an account
2. Go to the console → API Keys → click “New”
3. Copy the generated key (format: nix-xxxxxxxxxxxx)

Note: NixAPI charges per token with no monthly fee. Free credits are included on registration — more than enough to get started.

---

Step 2: Python Integration

Using the official openai SDK — only the base_url needs to change:

from openai import OpenAI

client = OpenAI(
    api_key="your-NixAPI-key",           # nix-xxxx format
    base_url="https://api.nixapi.com/v1", # replace this line
)

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "system",  "content": "You are a helpful assistant."},
        {"role": "user",    "content": "Hello, give me a brief introduction of yourself."},
    ],
    temperature=0.7,
    max_tokens=500,
)

print(response.choices[0].message.content)

That’s it! Your original OpenAI code works unchanged — just swap base_url and api_key.

---

Step 3: Node.js / TypeScript Integration

import OpenAI from 'openai';

const client = new OpenAI({
  apiKey: 'your-NixAPI-key',
  baseURL: 'https://api.nixapi.com/v1',
});

async function main() {
  const response = await client.chat.completions.create({
    model: 'claude-3-5-sonnet-20241022',  // Claude works the same way!
    messages: [
      { role: 'user', content: 'Explain Retrieval-Augmented Generation in 100 words' },
    ],
  });

  console.log(response.choices[0].message.content);
}

main();

---

Supported Models

NixAPI supports all major LLMs. Pass the model ID directly in your requests:

Model	Model ID	Highlights
GPT-4o	gpt-4o	OpenAI flagship, vision + text
GPT-4o mini	gpt-4o-mini	Low cost, fast
Claude 3.5 Sonnet	claude-3-5-sonnet-20241022	Excellent coding ability
Claude 3.5 Haiku	claude-3-5-haiku-20241022	Ultra-fast responses
Gemini 1.5 Pro	gemini-1.5-pro	Extra-long context window

The full model list is available in the NixAPI console and is updated regularly.

---

FAQ

Q: I’m currently using an OpenAI key. Can I simply swap it for a NixAPI key? A: Yes. The interface is 100% compatible — just change base_url and api_key.

Q: Does it support streaming output? A: Yes. Add stream: true to your request parameters. The format is identical to OpenAI.

Q: Is there a rate limit? A: Limits vary by plan. Check the NixAPI console for your current plan details.

---

Next Steps

• 👉 Register at NixAPI — free to start
• 📖 Streaming Tutorial — implement typewriter-style output
• 💸 Cost Optimization Guide — cut your API bill by 60%