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Introduction

BandChain.js is a comprehensive TypeScript library designed for seamless interaction with BandChain and Cosmos SDK blockchains. Built with modern web standards and developer experience in mind, it provides a complete toolkit for both blockchain queries and transaction execution.

Core Capabilities​

🔍 Query Client

  • REST & gRPC Integration: Built on gRPC-web protocol, sending HTTP/1.5 or HTTP/2 requests through a gRPC proxy server
  • Multi-Protocol Support: Access both Band Protocol-specific data (oracle requests, price feeds, TSS operations) and standard Cosmos modules (bank balances, staking info, governance proposals)
  • Type-Safe Queries: Fully typed query interfaces with auto-completion and compile-time validation
  • Cross-Platform: Native support for both Node.js environments and modern browsers

⚡ Message Composer

  • Type-Safe Transaction Building: Compose complex multi-message transactions with full TypeScript support
  • Dual Composition Patterns: Choose between fromPartial (message data only) and withTypeUrl (complete protobuf messages) based on your needs
  • Comprehensive Module Support: Pre-built message composers for all Band Protocol modules (oracle, feeds, tss, tunnel) and Cosmos SDK modules (bank, staking, governance, distribution, authz)
  • Batch Operations: Combine multiple operations in a single transaction for gas efficiency

🔐 Transaction Management

  • Wallet Integration: Seamless integration with popular Cosmos wallets (Keplr, Cosmostation, WalletConnect)
  • Signing Flexibility: Support for both online and offline signing workflows
  • Fee Estimation: Automatic gas estimation and fee calculation
  • Error Handling: Robust error handling with detailed transaction failure information

Technical Architecture​

The library is implemented using:

  • Protocol Buffer Code Generation: Automated TypeScript bindings generated from official proto definitions using @cosmology/telescope
  • CosmJS Integration: Built on top of the battle-tested CosmJS ecosystem for maximum compatibility
  • Dual Build System: Supports both CommonJS and ESM module formats for universal compatibility
  • Modern TypeScript: Full TypeScript 5.x support with strict type checking and comprehensive IDE support

The library supports both Node.js server environments and browser-based applications, making it the go-to solution for any TypeScript project interacting with BandChain or Cosmos SDK blockchains.