Access and Use Anthropic: Claude Sonnet 4.5 via OpenRouter using API Key
Ann Ng
Access and Use claude-sonnet-4.5 via OpenRouter
Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with improvements across system design, code security, and specification adherence. The model is designed for extended autonomous operation, maintaining task continuity across sessions and providing fact-based progress tracking.
Sonnet 4.5 also introduces stronger agentic capabilities, including improved tool orchestration, speculative parallel execution, and more efficient context and memory management. With enhanced context tracking and awareness of token usage across tool calls, it is particularly well-suited for multi-context and long-running workflows. Use cases span software engineering, cybersecurity, financial analysis, research agents, and other domains requiring sustained reasoning and tool use.
Anthropic: Claude Sonnet 4.5 Overview
| Full Name | Anthropic: Claude Sonnet 4.5 |
| Provider | Anthropic |
| Model ID | anthropic/claude-sonnet-4.5 |
| Release Date | Sep 29, 2025 |
| Context Window | 1,000,000 tokens |
| Pricing /1M tokens | $0.000003 for input $0.000015 for output $0.0048 for image |
| Supported Input Types | text, image, file |
| Supported Parameters | include_reasoningmax_tokensreasoningstoptemperaturetool_choicetoolstop_ktop_p |
Complete Setup Guide
Create OpenRouter Account
- Visit openrouter.ai
- Click "Sign In" and create an account (free)
- Verify your email address
- You'll receive $1 in free credits to test models
Get Your OpenRouter API Key
- Log in to OpenRouter dashboard
- Go to "API Keys" section in the menu
- Click "Create API Key"
- Give it a name (e.g., "TypingMind")
- Copy your API key (starts with "sk-or-v1-...")
Add Credits to OpenRouter (Optional)
- Go to "Credits" in OpenRouter dashboard
- Click "Add Credits"
- Choose amount ($5 minimum, $20 recommended for testing)
- Complete payment (credit card or crypto)
- Credits never expire!
Configure TypingMind with OpenRouter API Key
Method 1: Direct Import (Recommended)
- Open TypingMind in your browser
- Click the "Settings" icon (gear symbol)
- Navigate to "Manage Models" section
- Click "Add Custom Model"
- Select "Import OpenRouter" from the options
- Enter your OpenRouter API key from Step 1
- Click "Check API Key" to verify the connection
- Choose which models you want to add from the list (you can add multiple at once)
- Click "Import Models" to complete the setup
Method 2: Manual Custom Model Setup
- Open TypingMind in your browser
- Click the "Settings" icon (gear symbol)
- Navigate to "Models" section
- Click "Add Custom Model"
- Fill in the model information:Name:
anthropic/claude-sonnet-4.5 via OpenRouter(or your preferred name)Endpoint:https://openrouter.ai/api/v1/chat/completionsModel ID:anthropic/claude-sonnet-4.5Context Length: Enter the model's context window (e.g., 1000000 for anthropic/claude-sonnet-4.5)
anthropic/claude-sonnet-4.5https://openrouter.ai/api/v1/chat/completionsanthropic/claude-sonnet-4.5 via OpenRouterhttps://www.typingmind.com/model-logo.webp1000000 - Add custom headers by clicking "Add Custom Headers" in the Advanced Settings section:Authorization:
Bearer <OPENROUTER_API_KEY>:X-Title:typingmind.comHTTP-Referer:https://www.typingmind.com - Enable "Support Plugins (via OpenAI Functions)" if the model supports the "functions" or "tool_calls" parameter, or enable "Support OpenAI Vision" if the model supports vision.
- Click "Test" to verify the configuration
- If you see "Nice, the endpoint is working!", click "Add Model"
Start chatting with anthropic/claude-sonnet-4.5
Now you can start chatting with the anthropic/claude-sonnet-4.5 model via OpenRouter on TypingMind:
- Select your preferred anthropic/claude-sonnet-4.5 model from the model dropdown menu
- Start typing your message in the chat input
- Enjoy faster responses and better features than the official interface
- Switch between different AI models as needed
anthropic/claude-sonnet-4.5Pro tips for better results:
- Use specific, detailed prompts for better responses (How to use Prompt Library)
- Create AI agents with custom instructions for repeated tasks (How to create AI Agents)
- Use plugins to extend anthropic/claude-sonnet-4.5 capabilities (How to use plugins)
- Upload documents and images directly to chat for AI analysis and discussion (Chat with documents)
Why TypingMind + OpenRouter?
- Best-in-class UI: TypingMind's interface is far superior to standard chat UIs
- Model flexibility: Switch between Anthropic: Claude Sonnet 4.5 and 200+ models instantly
- Cost control: Pay only for what you use through OpenRouter
- One-time purchase: Buy TypingMind once, use forever with any OpenRouter model
- Data privacy: Your conversations stored locally, not on external servers
Frequently Asked Questions
Do I need a subscription to use Anthropic: Claude Sonnet 4.5?
No! Through OpenRouter, you pay only for what you use with no monthly subscription. Add credits to your OpenRouter account and they never expire. TypingMind is also a one-time purchase, not a subscription.
How much will it cost to use Anthropic: Claude Sonnet 4.5?
It costs 0.000003 for input and 0.000015 for output via OpenRouter. A typical conversation might cost $0.01-0.10 depending on length. Start with $5-10 in credits to test.
Can I use other models besides Anthropic: Claude Sonnet 4.5?
Yes! With OpenRouter + TypingMind, you get access to 200+ models including GPT-4, Claude, Gemini, Llama, Mistral, and many more. Switch between them instantly in TypingMind.
Is my data private and secure?
Yes! TypingMind stores conversations locally (web version in browser, desktop version on your device). OpenRouter handles API calls securely and doesn't train on your data. Check each provider's data policy for specifics.
Can I use Anthropic: Claude Sonnet 4.5 for commercial projects?
Yes! Check Anthropic's terms of service for specific commercial use policies. OpenRouter and TypingMind both support commercial use.
What if Anthropic: Claude Sonnet 4.5 is unavailable?
OpenRouter allows you to configure fallback models. If Anthropic: Claude Sonnet 4.5 is down, it can automatically route to your backup choice. You can also manually switch models in TypingMind anytime.
How do I cancel or get a refund?
OpenRouter: No subscriptions to cancel. Unused credits remain in your account forever.
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