How to Use OpenRouter with Claude Code Through Prism

OpenRouter is a unified API gateway that provides access to hundreds of models from dozens of providers through a single endpoint. Instead of managing separate API keys for Anthropic, OpenAI, DeepSeek, Groq, Mistral, and more, you get one key and one base URL that routes to any model you want.

Combining OpenRouter with Prism and Claude Code gives you the best of all worlds: Claude Code's agent capabilities, OpenRouter's model breadth, and Prism's transparent format translation. You can switch between GPT-4o, DeepSeek, Llama, Gemini, and hundreds of others just by changing a model name in your remapping config.

Why OpenRouter

The main appeal is breadth. Over 300 models are available through one API, including models from providers that do not offer direct API access. OpenRouter also handles failover automatically — if one provider is down, it can route to a backup. Pricing is transparent and pay-as-you-go, often matching the underlying provider's rates.

Step by step

Manual environment variables

$env:ANTHROPIC_BASE_URL = "http://127.0.0.1:11434"
    $env:ANTHROPIC_AUTH_TOKEN = "prism"

Model remapping

Map Claude Code's Anthropic model names to OpenRouter models:

// %APPDATA%\prism\model_remapping.json
    {
      "default_model": "deepseek/deepseek-chat",
      "known_models": [
        { "id": "deepseek/deepseek-chat",            "provider": "custom_openrouter" },
        { "id": "meta-llama/llama-3.3-70b-instruct", "provider": "custom_openrouter" },
        { "id": "google/gemini-2.5-pro",             "provider": "custom_openrouter" }
      ],
      "aliases": {
        "claude-3-5-sonnet-20241022": "deepseek/deepseek-chat",
        "claude-3-5-haiku-20241022":  "meta-llama/llama-3.3-70b-instruct",
        "claude-3-opus-20240229":     "google/gemini-2.5-pro"
      }
    }

Using multiple models

One of the biggest advantages of OpenRouter is that you can mix models from different providers in a single configuration. You are not locked to one provider's model family. Your per-tier remapping can draw from completely different providers:

// Per-tier selection lives in Claude Code, not in the remapping file
    ANTHROPIC_DEFAULT_OPUS_MODEL   = "google/gemini-2.5-pro"
    ANTHROPIC_DEFAULT_SONNET_MODEL = "deepseek/deepseek-chat"
    ANTHROPIC_DEFAULT_HAIKU_MODEL  = "meta-llama/llama-3.3-70b-instruct"
    CLAUDE_CODE_SUBAGENT_MODEL     = "qwen/qwen-2.5-coder-32b-instruct"

This per-tier approach lets you use premium models only where they matter most, while keeping costs down with cheaper models for background and sub-agent work. Because OpenRouter handles the routing to each underlying provider, you only need one API key.

Config example

// %APPDATA%\prism\config.json
    {
      "custom_providers": [
        {
          "id": "custom_openrouter_7g8h9i",
          "name": "OpenRouter",
          "base_url": "https://openrouter.ai/api/v1",
          "api_key": "sk-or-v1-your-key"
        }
      ]
    }

Get started

Download Prism, add OpenRouter as a custom provider, remap your models, and start Claude Code. You will have access to hundreds of models through a single API key in minutes.

Download Prism