OpenRouter Rust SDK

🌟 What makes this special?

• 🔒 Type Safety: Leverages Rust's type system for compile-time error prevention
• ⚡ Async/Await: Built on tokio for high-performance concurrent operations
• 🧠 Reasoning Tokens: Industry-leading chain-of-thought reasoning support
• 📡 Streaming: Real-time response streaming with futures
• 🏗️ Builder Pattern: Ergonomic client and request construction
• ⚙️ Smart Presets: Curated model groups for programming, reasoning, and free tiers
• 🎯 Complete Coverage: All OpenRouter API endpoints supported

🚀 Quick Start

Installation

Add to your Cargo.toml:

[dependencies]
openrouter-rs = "0.4.5"
tokio = { version = "1", features = ["full"] }

30-Second Example

use openrouter_rs::{OpenRouterClient, api::chat::*, types::Role};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create client
    let client = OpenRouterClient::builder()
        .api_key("your_api_key")
        .build()?;

    // Send chat completion
    let request = ChatCompletionRequest::builder()
        .model("anthropic/claude-sonnet-4")
        .messages(vec![
            Message::new(Role::User, "Explain Rust ownership in simple terms")
        ])
        .build()?;

    let response = client.send_chat_completion(&request).await?;
    println!("{}", response.choices[0].content().unwrap_or(""));

    Ok(())
}

✨ Key Features

🧠 Advanced Reasoning Support

Leverage chain-of-thought processing with reasoning tokens:

use openrouter_rs::types::Effort;

let request = ChatCompletionRequest::builder()
    .model("deepseek/deepseek-r1")
    .messages(vec![Message::new(Role::User, "What's bigger: 9.9 or 9.11?")])
    .reasoning_effort(Effort::High)    // Enable deep reasoning
    .reasoning_max_tokens(2000)        // Control reasoning depth
    .build()?;

let response = client.send_chat_completion(&request).await?;

// Access both reasoning and final answer
println!("🧠 Reasoning: {}", response.choices[0].reasoning().unwrap_or(""));
println!("💡 Answer: {}", response.choices[0].content().unwrap_or(""));

📡 Real-time Streaming

Process responses as they arrive:

use futures_util::StreamExt;

let stream = client.stream_chat_completion(&request).await?;

stream
    .filter_map(|event| async { event.ok() })
    .for_each(|chunk| async move {
        if let Some(content) = chunk.choices[0].content() {
            print!("{}", content);  // Print as it arrives
        }
    })
    .await;

⚙️ Smart Model Presets

Use curated model collections:

use openrouter_rs::config::OpenRouterConfig;

let config = OpenRouterConfig::default();

// Three built-in presets:
// • programming: Code generation and development
// • reasoning: Advanced problem-solving models  
// • free: Free-tier models for experimentation

println!("Available models: {:?}", config.get_resolved_models());

🛡️ Comprehensive Error Handling

use openrouter_rs::error::OpenRouterError;

match client.send_chat_completion(&request).await {
    Ok(response) => println!("Success!"),
    Err(OpenRouterError::ModerationError { reasons, .. }) => {
        eprintln!("Content flagged: {:?}", reasons);
    }
    Err(OpenRouterError::ApiError { code, message }) => {
        eprintln!("API error {}: {}", code, message);
    }
    Err(e) => eprintln!("Other error: {}", e),
}

📊 API Coverage

🎯 More Examples

Filter Models by Category

use openrouter_rs::types::ModelCategory;

let models = client
    .list_models_by_category(ModelCategory::Programming)
    .await?;

println!("Found {} programming models", models.len());

Advanced Client Configuration

let client = OpenRouterClient::builder()
    .api_key("your_key")
    .http_referer("https://yourapp.com")
    .x_title("My AI App")
    .base_url("https://openrouter.ai/api/v1")  // Custom endpoint
    .build()?;

Streaming with Reasoning

let stream = client.stream_chat_completion(
    &ChatCompletionRequest::builder()
        .model("anthropic/claude-sonnet-4")
        .messages(vec![Message::new(Role::User, "Solve this step by step: 2x + 5 = 13")])
        .reasoning_effort(Effort::High)
        .build()?
).await?;

let mut reasoning_buffer = String::new();
let mut content_buffer = String::new();

stream.filter_map(|event| async { event.ok() })
    .for_each(|chunk| async {
        if let Some(reasoning) = chunk.choices[0].reasoning() {
            reasoning_buffer.push_str(reasoning);
            print!("🧠");  // Show reasoning progress
        }
        if let Some(content) = chunk.choices[0].content() {
            content_buffer.push_str(content);
            print!("💬");  // Show content progress
        }
    }).await;

println!("\n🧠 Reasoning: {}", reasoning_buffer);
println!("💡 Answer: {}", content_buffer);

📚 Documentation & Resources

• 📖 API Documentation - Complete API reference
• 🎯 Examples Repository - Comprehensive usage examples
• 🔧 Configuration Guide - Model presets and configuration
• ⚡ OpenRouter API Docs - Official OpenRouter documentation

Run Examples Locally

# Set your API key
export OPENROUTER_API_KEY="your_key_here"

# Basic chat completion
cargo run --example send_chat_completion

# Reasoning tokens demo
cargo run --example chat_with_reasoning

# Streaming responses
cargo run --example stream_chat_completion

# Run with reasoning
cargo run --example stream_chat_with_reasoning

🤝 Community & Support

🐛 Found a Bug?

Please open an issue with:

• Your Rust version (rustc --version)
• SDK version you're using
• Minimal code example
• Expected vs actual behavior

💡 Feature Requests

We love hearing your ideas! Start a discussion to:

• Suggest new features
• Share use cases
• Get help with implementation

🛠️ Contributing

Contributions are welcome! Please see our contributing guidelines:

1. Fork the repository
2. Create a feature branch
3. Add tests for new functionality
4. Follow the existing code style
5. Submit a pull request

⭐ Show Your Support

If this SDK helps your project, consider:

• ⭐ Starring the repository
• 🐦 Sharing on social media
• 📝 Writing about your experience
• 🤝 Contributing improvements

📋 Requirements

• Rust: 1.85+ (2024 edition)
• Tokio: 1.0+ (for async runtime)
• OpenRouter API Key: Get yours here

🗺️ Roadmap

• WebSocket Support - Real-time bidirectional communication
• Retry Strategies - Automatic retry with exponential backoff
• Caching Layer - Response caching for improved performance
• CLI Tool - Command-line interface for quick testing
• Middleware System - Request/response interceptors

📜 License

This project is licensed under the MIT License - see the LICENSE file for details.

⚠️ Disclaimer

This is a third-party SDK not officially affiliated with OpenRouter. Use at your own discretion.

📈 Release History

Version 0.4.5 (Latest)

• 🧠 New: Complete reasoning tokens implementation with chain-of-thought support
• ⚙️ Updated: Model presets restructured to programming/reasoning/free categories
• 📚 Enhanced: Professional-grade documentation with comprehensive examples
• 🏗️ Improved: Configuration system with better model management

Version 0.4.4

• Added: Support for listing models by supported parameters
• Note: OpenRouter API limitations on simultaneous category and parameter filtering

Version 0.4.3

• Added: Support for listing models by category
• Thanks to OpenRouter team for the API enhancement!