Hermes 4 405B

Hermes 4 is a large-scale reasoning model built on Meta-Llama-3.1-405B and released by Nous Research.

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{
  "model": "nousresearch/hermes-4-405b",
  "baseURL": "https://openrouter.ai/api/v1"
}

OpenAI-compatible API: point any OpenAI SDK at the base URL and use this model id.

Settings it needs

OPENROUTER_API_KEYrequiredsecret

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About

Hermes 4 is a large-scale reasoning model built on Meta-Llama-3.1-405B and released by Nous Research. It introduces a hybrid reasoning mode, where the model can choose to deliberate internally with...

Use cases: model-inference

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Price and limits

Variant	Input $/M tokens	Output $/M tokens	Cached input $/M
Standard	$1	$3	—

Price as of Oct 26, 2026 from OpenRouter. Prices change often; check before you rely on one.

Provider: Nous Research
Model id: nousresearch/hermes-4-405b
Context window: 131,072 tokens (131K)
Max output: 117,964 tokens
Input: text
Output: text
Tool calling: Not listed
Structured outputs: Yes
Reasoning: Yes
Weights: Open: NousResearch/Hermes-4-405B
Released: Aug 26, 2025
Knowledge cutoff: 2024-08-31

Details

Auth: API key
License: License unknown
Website: nousresearch.com
Docs: openrouter.ai/nousresearch/hermes-4-405b/api
First seen: Oct 24, 2026
Last checked: Oct 26, 2026
Source: OpenRouter

More from Nous Research

Cite this page

Hermes 4 405B: price, context window, tool use. Agent Mart. https://agentmart.dev/models/nousresearch-hermes-4-405b (last updated 2026-10-26)