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1.OpenRouter Large Model API Aggregation Platform

Concept Introduction​

1.1 What is "OpenRouter"?​

OpenRouter is a large model API aggregation platform. It provides a unified API interface (compatible with the OpenAI API format) that allows developers to access multiple large language models using a single API key.

Instead of managing separate accounts and APIs for platforms such as OpenAI, Anthropic, or Google, OpenRouter offers a single entry point to both open-source and commercial models.

Core Advantages​

  • Model Flexibility – Switch between GPT, Claude, Llama, Gemini, and other models by changing configuration only.
  • Cost Transparency – Easily compare pricing across different models.
  • Rapid Access to New Models – Newly released models are often available quickly.

To enable OpenRouter in the largemodel project, set:

llm_platform: openrouter

2. Practical Operations​

2.1 Obtaining API Credentials​

  1. Register an account at: https://openrouter.ai/
  2. Add credits (optional). Free models are available but may have rate limits.
  3. Navigate to Keys and generate a new API key.
  4. Copy and securely store the API key.

2.2 Graphical Walkthrough​

  1. Visit the OpenRouter website:

OpenRouter homepage

  1. Register and sign in.
  2. Open the model marketplace.

OpenRouter model marketplace

  1. Search for free models.

Search free models

  1. Copy the model identifier using the clipboard icon.

Copy model identifier

  1. Open Keys from the profile menu.

Open API keys menu

  1. Create a new API key.

Create API key

  1. Copy and save the API key securely.

API key generated

2.3 Configuration File Modifications​

Step 1: Configure OpenRouter in large_model_interface.yaml​

vim ~/hemihex_ws/src/largemodel/config/large_model_interface.yaml

Example configuration:

# OpenRouter Platform Configuration
openrouter_api_key: "sk-xxxxxxxxxxxxxxxxxxx"
openrouter_model: "moonshotai/kimi-k2:free"

Step 2: Switch Platform in hemihex.yaml​

vim ~/hemihex_ws/src/largemodel/config/hemihex.yaml

Update the platform:

llm_platform: 'openrouter'

Step 3: Rebuild the Workspace​

After updating configuration files, rebuild the workspace to apply changes.

Notes​

  • Keep API keys private and out of version control.
  • Free-tier models may have request or performance limits.

This documentation is maintained by HemiHex and describes how to use OpenRouter as an online large-model backend.