Chainlink CRE SDK for TypeScript

Build decentralized workflows that combine off-chain computation with on-chain execution using the Chainlink Runtime Environment (CRE) SDK.

What is CRE?

The Chainlink Runtime Environment enables developers to create workflows that:

• Fetch data from external APIs with built-in consensus
• Interact with blockchains across multiple networks
• Coordinate complex operations with triggers and scheduling
• Aggregate results from multiple data sources reliably

Perfect for building price feeds, automated trading strategies, cross-chain applications, and any workflow requiring reliable off-chain computation with on-chain execution.

Package Structure

This monorepo contains:

• @chainlink/cre-sdk - Main SDK for building CRE workflows
• @chainlink/cre-sdk-examples - Example workflows and patterns
• @chainlink/cre-sdk-javy-plugin - WebAssembly compilation tools

Examples

📅 Scheduled Tasks

// Execute every 5 minutes
const cron = new cre.capabilities.CronCapability();
cron.trigger({ schedule: "0 */5 * * * *" });

🌐 API Data Fetching

// Fetch with built-in consensus across nodes
const price = await cre.runInNodeMode(
  fetchPriceData,
  consensusMedianAggregation()
)(config);

⛓️ Blockchain Integration

// Read/write to any EVM chain
const evmClient = new cre.capabilities.EVMClient(
  undefined,
  BigInt("5009297550715157269") // Ethereum Sepolia
);

Key Features

• 🔄 Multi-Node Consensus - Aggregate data from multiple sources reliably
• ⚡ Cross-Chain Support - Work with 200+ blockchain networks
• 📊 Built-in Aggregation - Median, mean, and custom consensus mechanisms
• 🛡️ Type Safety - Full TypeScript support with Zod validation
• 🎯 Event-Driven - Cron triggers, HTTP webhooks, and custom events
• 🔗 Viem Integration - Native support for Ethereum interactions

Use Cases

🏦 DeFi Applications

• Automated yield farming strategies
• Cross-chain arbitrage bots
• Dynamic rebalancing portfolios
• Liquidation protection systems

📊 Data Oracles

• Custom price feeds with multiple sources
• Weather data aggregation
• Sports scores and betting odds
• Real-world asset tokenization data

🔗 Cross-Chain Operations

• Bridge monitoring and alerts
• Multi-chain governance voting
• Cross-chain token transfers
• Unified liquidity management

Contributing & Development

This monorepo uses:

• Bun - Package manager and TypeScript runtime
• Biome - Formatting and linting
• Javy - WebAssembly compilation

Setup for Contributors

# Clone with submodules (for protobuf definitions)
git clone --recursive https://github.com/smartcontractkit/cre-sdk-typescript
cd cre-sdk-typescript

# Install dependencies
bun install

# Build everything
bun build

Available Scripts

# Development
bun build                 # Build all packages using turbo
bun check                 # Format and lint code using biome
bun format                # Format code using biome
bun lint                  # Lint code using biome
bun typecheck             # Type check all packages

# Package-specific builds (run from packages/cre-sdk/)
bun generate:proto        # Generate types from protobuf
bun generate:chain-selectors  # Update chain selector types
bun generate:sdk          # Generate all SDK types and code

For detailed development setup, see individual package READMEs:

• CRE SDK Development
• Javy Plugin Development

Submodules

This project uses Git submodules for external dependencies:

# Clone with submodules
git clone --recursive https://github.com/smartcontractkit/cre-sdk-typescript

# Or initialize submodules after cloning
git submodule update --init --recursive

# Update submodules to latest
git submodule update --remote

Current submodules:

• chainlink-protos - Protocol buffer definitions

License

See LICENSE in individual package directories.