Polyfill-rs provides a comprehensive trading infrastructure for algorithmic trading strategies on Polymarket's prediction markets. The library is designed for institutional-grade trading systems requiring high throughput and robust error handling.

Key Features:

Drop-in replacement for polymarket-rs-client with enhanced functionality
High-performance order book management with O(log n) operations
Real-time market data streaming with WebSocket support
Trade execution simulation with slippage protection
Comprehensive error handling with specific error types

Migration from polymarket-rs-client

Polyfill-rs is designed as a drop-in replacement for the existing polymarket-rs-client. The API maintains full compatibility while adding advanced features:

// Before (polymarket-rs-client)
use polymarket_rs_client::ClobClient;

let mut client = ClobClient::with_l1_headers(
    "https://clob.polymarket.com",
    "your_private_key",
    137,
);

// After (polyfill-rs) - Same API!
use polyfill_rs::ClobClient;

let mut client = ClobClient::with_l1_headers(
    "https://clob.polymarket.com", 
    "your_private_key",
    137,
);

// All existing methods work identically
let api_creds = client.create_or_derive_api_key(None).await?;
client.set_api_creds(api_creds);

let order_args = OrderArgs::new(
    "token_id",
    Decimal::from_str("0.75")?,
    Decimal::from_str("100.0")?,
    Side::BUY,
);

let result = client.create_and_post_order(&order_args).await?;

Architecture

Core Components

Order Book Management

Real-time order book maintenance with O(log n) operations
Thread-safe concurrent access patterns
Market impact calculation and liquidity analysis
Snapshot generation for strategy backtesting

Trade Execution Engine

Market order simulation with slippage protection
Limit order placement and management
Fill event processing and tracking
Fee calculation and cost analysis

Streaming Infrastructure

WebSocket-based real-time market data feeds
Automatic reconnection with exponential backoff
Message parsing and validation
Multi-stream management for concurrent market monitoring

Client Interface

REST API integration for order management
Authentication and signature generation
Rate limiting and request throttling
Comprehensive error handling with retry logic

Performance Characteristics

Latency Optimization

Zero-copy data structures where possible
Lock-free concurrent access patterns
Minimal allocation in hot paths
SIMD-optimized mathematical operations

Throughput Capabilities

High-frequency order book updates (10,000+ updates/second)
Concurrent stream processing
Efficient memory management with object pooling
Optimized serialization/deserialization

Memory Efficiency

Compact data representations
Minimal heap allocations
Efficient string handling
Memory-mapped data structures for large datasets

Installation

Add to your Cargo.toml:

[dependencies]
polyfill-rs = "0.1.0"

Usage

Basic Client Initialization (Compatible with polymarket-rs-client)

use polyfill_rs::{ClobClient, OrderArgs, Side};
use rust_decimal::Decimal;

let mut client = ClobClient::with_l1_headers(
    "https://clob.polymarket.com",
    "your_private_key",
    137,
);

// Get API credentials
let api_creds = client.create_or_derive_api_key(None).await?;
client.set_api_creds(api_creds);

// Create and post order
let order_args = OrderArgs::new(
    "token_id",
    Decimal::from_str("0.75")?,
    Decimal::from_str("100.0")?,
    Side::BUY,
);

let result = client.create_and_post_order(&order_args).await?;

Advanced Features (Polyfill-rs specific)

use polyfill_rs::{PolyfillClient, ClientConfig};

// Advanced configuration
let config = ClientConfig {
    base_url: "https://clob.polymarket.com".to_string(),
    chain_id: 137,
    private_key: Some("your_private_key".to_string()),
    max_slippage: Some(Decimal::from_str("0.001")?),
    fee_rate: Some(Decimal::from_str("0.02")?),
    ..Default::default()
};

let mut client = PolyfillClient::with_config(config)?;

// Subscribe to real-time order book updates
client.subscribe_to_order_book("token_id").await?;

// Process incoming messages
while let Some(message) = client.get_next_message().await? {
    println!("Received: {:?}", message);
}

Order Book Management

use polyfill_rs::{OrderBookManager, OrderDelta, Side};

let mut book_manager = OrderBookManager::new();

// Apply order book delta
let delta = OrderDelta {
    token_id: "market_token".to_string(),
    timestamp: chrono::Utc::now(),
    side: Side::Buy,
    price: Decimal::from_str("0.75")?,
    size: Decimal::from_str("100.0")?,
    sequence: 1,
};

book_manager.apply_delta(delta)?;

// Retrieve order book state
let book = book_manager.get_book("market_token")?;
let best_bid = book.best_bid();
let best_ask = book.best_ask();
let spread = book.spread();

Trade Execution Simulation

use polyfill_rs::{FillEngine, MarketOrderRequest};

let mut fill_engine = FillEngine::new(
    Decimal::from_str("0.001")?, // max_slippage
    Decimal::from_str("0.02")?,  // fee_rate
);

let order = MarketOrderRequest {
    token_id: "market_token".to_string(),
    side: Side::Buy,
    size: Decimal::from_str("50.0")?,
    max_price: Some(Decimal::from_str("0.80")?),
};

let result = fill_engine.execute_market_order(&book, order)?;
println!("Filled: {} at avg price: {}", result.filled_size, result.average_price);

Real-time Market Data

use polyfill_rs::{StreamManager, WebSocketStream};

let mut stream_manager = StreamManager::new();

// Subscribe to order book updates
let stream = WebSocketStream::new("wss://clob.polymarket.com/ws").await?;
stream_manager.add_stream("orderbook", stream).await?;

// Process incoming messages
while let Some(message) = stream_manager.next().await {
    match message {
        Ok(msg) => {
            // Process order book update
            if let Some(delta) = msg.to_order_delta() {
                book_manager.apply_delta(delta)?;
            }
        }
        Err(e) => {
            // Handle connection errors
            eprintln!("Stream error: {}", e);
        }
    }
}

Demo Trading Strategy

use polyfill_rs::{PolyfillClient, OrderBookManager, FillEngine};

struct ArbitrageStrategy {
    client: PolyfillClient,
    book_manager: OrderBookManager,
    fill_engine: FillEngine,
    min_spread: Decimal,
    position_size: Decimal,
}

impl ArbitrageStrategy {
    async fn execute_arbitrage(&mut self, token_id: &str) -> Result<()> {
        let book = self.book_manager.get_book(token_id)?;
        
        // Calculate arbitrage opportunity
        let spread = book.spread();
        if spread < self.min_spread {
            return Ok(());
        }
        
        let mid_price = book.mid_price();
        let bid_price = book.best_bid().unwrap().price;
        let ask_price = book.best_ask().unwrap().price;
        
        // Execute cross-spread orders
        let buy_order = self.client.create_order(
            token_id,
            Side::Buy,
            self.position_size,
            Some(bid_price),
        ).await?;
        
        let sell_order = self.client.create_order(
            token_id,
            Side::Sell,
            self.position_size,
            Some(ask_price),
        ).await?;
        
        Ok(())
    }
}

Configuration

Performance Tuning

use polyfill_rs::Config;

let config = Config {
    // Network configuration
    base_url: "https://clob.polymarket.com".to_string(),
    chain_id: 137,
    
    // Authentication
    private_key: Some("your_private_key".to_string()),
    api_credentials: None,
    
    // Performance settings
    connection_timeout: Duration::from_secs(5),
    request_timeout: Duration::from_secs(10),
    max_retries: 3,
    retry_delay: Duration::from_millis(100),
    
    // Rate limiting
    requests_per_second: 100,
    burst_size: 10,
};

Order Book Configuration

use polyfill_rs::OrderBookManager;

let book_manager = OrderBookManager::with_config(OrderBookConfig {
    max_books: 1000,
    cleanup_interval: Duration::from_secs(300),
    max_sequence_gap: 1000,
});

Error Handling

The library provides comprehensive error handling with specific error types:

use polyfill_rs::errors::{PolyfillError, ErrorKind};

match result {
    Ok(data) => {
        // Process successful response
    }
    Err(PolyfillError::Network { .. }) => {
        // Handle network connectivity issues
    }
    Err(PolyfillError::RateLimit { retry_after, .. }) => {
        // Implement exponential backoff
        tokio::time::sleep(retry_after).await;
    }
    Err(PolyfillError::Order { order_id, .. }) => {
        // Handle order-specific errors
    }
    Err(e) => {
        // Handle other errors
        eprintln!("Unexpected error: {}", e);
    }
}

Testing and Benchmarking

Unit Tests

cargo test

Performance Benchmarks

cargo bench

Example Execution

cargo run --example snipe

API Reference

Comprehensive API documentation is available at docs.rs/polyfill-rs.

License

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

Contributing

Contributions are welcome. Please ensure all code follows the established patterns and includes appropriate tests and benchmarks.