Nous: Hermes 3 405B Instruct (free) — Free API

What is Nous: Hermes 3 405B Instruct (free)?

Nous Research Hermes 3 405B is a frontier-level, full-parameter finetune of Llama 3.1 405B, available free on OpenRouter. It builds on Hermes 2 with advanced agentic capabilities, roleplaying, multi-turn conversation, and long-context coherence. Features powerful and reliable function calling, structured output capabilities, and improved code generation. Emphasizes user alignment — providing strong steering control to the end user. 131K context window. Text-only. OpenAI-compatible via OpenRouter. Free tier: 200 RPD.

Nous: Hermes 3 405B Instruct (free) API Code Example

Paste your API key and run. See the config generator for Claude Code, Cursor, and more tools.

from openai import OpenAI

client = OpenAI(
    base_url="https://openrouter.ai/api/v1",
    api_key="YOUR_API_KEY"
)

response = client.chat.completions.create(
    model="nousresearch/hermes-3-llama-3.1-405b:free",
    messages=[{"role": "user", "content": "Hello!"}]
)
print(response.choices[0].message.content)

import OpenAI from "openai";

const openai = new OpenAI({
  baseURL: "https://openrouter.ai/api/v1",
  apiKey: "YOUR_API_KEY",
});

const completion = await openai.chat.completions.create({
  model: "nousresearch/hermes-3-llama-3.1-405b:free",
  messages: [{ role: "user", content: "Hello!" }],
});

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

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "nousresearch/hermes-3-llama-3.1-405b:free",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Other Free Models from OpenRouter