---
title: Hermes 4 405B — Reasoning LLM | ModelsLab
description: Deploy Hermes 4 405B's hybrid reasoning model. Toggle deep thinking for math, code, and logic. Try the frontier LLM with 131K context.
url: https://modelslab.com/nous-hermes-4-405b
canonical: https://modelslab.com/nous-hermes-4-405b
type: website
component: Seo/ModelPage
generated_at: 2026-04-15T02:02:52.307785Z
---

Available now on ModelsLab · Language Model

Nous: Hermes 4 405B
Reasoning. Your way.
---

[Try Nous: Hermes 4 405B](/models/open_router/nousresearch-hermes-4-405b) [API Documentation](https://docs.modelslab.com)

Hybrid reasoning meets production speed
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Toggleable Reasoning

### Deep thinking on demand

Switch between instant responses and internal deliberation with think tags for complex problems.

Frontier Performance

### Math, code, logic mastery

accuracy on reasoning benchmarks with 100% reliability across evaluations.

Massive Context

### 131K token window

Process long documents, codebases, and multi-turn conversations without truncation.

Examples

See what Nous: Hermes 4 405B can create
---

Copy any prompt below and try it yourself in the [playground](/models/open_router/nousresearch-hermes-4-405b).

Mathematical Problem

“Solve this differential equation step-by-step: d²y/dx² + 4dy/dx + 3y = e^(-x). Show all work and reasoning.”

Code Optimization

“Review this Python function for performance bottlenecks and suggest optimizations with complexity analysis.”

Logic Puzzle

“Five people sit around a table. Given these constraints, determine who sits where and explain your reasoning.”

Technical Analysis

“Analyze this system architecture diagram and identify potential failure points and scalability issues.”

For Developers

A few lines of code.
Reasoning model. Three lines.
---

ModelsLab handles the infrastructure: fast inference, auto-scaling, and a developer-friendly API. No GPU management needed.

- **Serverless:** scales to zero, scales to millions
- **Pay per token,** no minimums
- **Python and JavaScript SDKs,** plus REST API

[API Documentation ](https://docs.modelslab.com)

PythonJavaScriptcURL

Copy

```
<code>import requests

response = requests.post(
    "https://modelslab.com/api/v7/llm/chat/completions",
    json={
  "key": "YOUR_API_KEY",
  "prompt": "",
  "model_id": ""
}
)
print(response.json())</code>
```

FAQ

Common questions about Nous: Hermes 4 405B
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[Read the docs ](https://docs.modelslab.com)

### What is Nous Hermes 4 405B?

### How does hybrid reasoning work?

### What's the context window size?

### Does it support structured outputs?

### How accurate is Hermes 4 405B?

### Is this model open-weight?

Ready to create?
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Start generating with Nous: Hermes 4 405B on ModelsLab.

[Try Nous: Hermes 4 405B](/models/open_router/nousresearch-hermes-4-405b) [API Documentation](https://docs.modelslab.com)

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*This markdown version is optimized for AI agents and LLMs.*

**Links:**
- [Website](https://modelslab.com)
- [API Documentation](https://docs.modelslab.com)
- [Blog](https://modelslab.com/blog)

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*Generated by ModelsLab - 2026-04-15*