apex-sdk

Apex SDK Protocol Documentation Hub

Your complete guide to building cross-chain applications with Apex SDK

Getting Started

New to Apex SDK? Start here:

Guide	Time	Description
Quick Start Guide	5 min	Get your first cross-chain app running
CLI Guide	10 min	Master the command-line tools
API Reference	Reference	Complete API documentation

Core Documentation

Development Guides

Basic Concepts

- [Quick Start](/apex-sdk/docs/QUICK_START.html) - Get started in 5 minutes - [Project Structure](#project-structure) - Understand the codebase - [Configuration](/apex-sdk/docs/CLI_GUIDE.html#configuration) - Configure your SDK - [Error Handling](#error-handling) - Handle errors gracefully

Building Applications

- [Substrate Integration](#substrate) - Connect to Substrate chains - [EVM Integration](#evm) - Connect to EVM chains - [Cross-Chain Transactions](#cross-chain) - Bridge between ecosystems - [Smart Contracts](#contracts) - Deploy and interact with contracts

Security & Best Practices

- [Security Guide](/apex-sdk/docs/SECURITY.html) - Secure your application - [Security Audit](/apex-sdk/docs/SECURITY_AUDIT.html) - Review security audit results - [Best Practices](#best-practices) - Production-ready code - [Testing Framework](/apex-sdk/docs/TESTING_FRAMEWORK.html) - Write comprehensive tests

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By Use Case

Find documentation specific to your needs:

DeFi Applications

• Token Swaps - Build DEX integrations
• Yield Farming - Aggregate yields across chains
• Liquidity Pools - Manage cross-chain liquidity

NFT Applications

• NFT Minting - Create and mint NFTs
• NFT Bridging - Transfer NFTs across chains
• NFT Marketplaces - Build marketplaces

DAO & Governance

• Voting Systems - Implement cross-chain voting
• Treasury Management - Manage multi-chain treasuries
• Membership - Handle cross-chain memberships

Infrastructure

• Oracle Services - Build price oracles
• Event Indexing - Index blockchain events
• RPC Services - Set up RPC infrastructure

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Developer Tools

CLI Commands

# Project Management
apex new <name>          # Create new project
apex build              # Build project
apex test               # Run tests

# Chain Operations
apex chain list         # List supported chains
apex chain info <name>  # Get chain information

# Documentation (Current Status)
apex account generate   # Not implemented - see alternatives
apex account import     # Not implemented - see alternatives
apex deploy             # Not implemented - see alternatives

Note: Some CLI features are in development. See UX Improvements Applied for current status and alternatives.

Configuration Files

• .apex/config.json - Project configuration
• Cargo.toml - Dependencies and metadata
• .github/workflows/ - CI/CD pipelines

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Examples & Templates

Quick Start Examples

Example	Chains	Description
Account Manager	Multi-chain	Manage accounts across ecosystems
Price Oracle	Polkadot + ETH	Aggregate prices cross-chain
Contract Orchestration	EVM	Deploy and manage contracts
Parachain Assets	Substrate	Work with parachain assets

Project Templates

# DeFi template
apex new my-defi --template defi

# NFT template
apex new my-nft --template nft

# Basic template (default)
apex new my-app --template basic

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API Reference

Core Modules

Module	Description	Documentation
apex_sdk	Main SDK interface	API Docs
apex_sdk_substrate	Substrate adapter	API Docs
apex_sdk_evm	EVM adapter	API Docs
apex_sdk_types	Shared types	API Docs
apex_sdk_core	Core traits	API Docs

Key Types

• ApexSDK - Main SDK struct
• Transaction - Cross-chain transaction
• Chain - Blockchain enumeration
• Address - Multi-chain address type
• TransactionResult - Execution result

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Testing & Quality

Testing Tools

• Testing Framework - Comprehensive test suite
• Benchmarking - Performance testing
• Integration Tests - End-to-end testing

Quality Assurance

• Type Safety - Compile-time checks with Rust
• Security Audits - View audit results
• CI/CD - Automated testing on every commit
• Code Coverage - Minimum 80% coverage required

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Supported Blockchains

Substrate Ecosystem

• Polkadot - Relay chain (Stable)
• Kusama - Canary network (Stable)
• Westend - Testnet (In Development)
• Parachains - Moonbeam, Astar, Acala (In Development)

EVM Ecosystem

• Ethereum - Mainnet (Stable)
• BSC - Binance Smart Chain (Stable)
• Polygon - Matic Network (Stable)
• Avalanche - C-Chain (Stable)
• Arbitrum - L2 (Coming soon)
• Optimism - L2 (Coming soon)

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Community & Support

Get Help

• GitHub Discussions - Ask questions
• Issue Tracker - Report bugs
• Security Reports - Report vulnerabilities
• Contributing Guide - Contribute code

Stay Updated

• Star on GitHub
• Changelog - Latest changes
• Roadmap - Upcoming features

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What’s Next?

See our Development Roadmap for:

• Planned features
• Timeline and milestones
• How to contribute
• Community priorities

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Quick Reference

Common Tasks

Initialize a new project:

apex new my-app && cd my-app

Connect to chains:

let sdk = ApexSDK::builder()
    .with_substrate(Chain::Polkadot, "wss://rpc.polkadot.io")
    .with_evm(Chain::Ethereum, "https://eth.llamarpc.com")
    .build().await?;

Execute a transaction:

let tx = sdk.transaction()
    .from_substrate_account("5GrwvaEF...")
    .to_evm_address("0x742d35Cc...")
    .amount(1000)
    .build()?;

let result = sdk.execute(tx).await?;

Check balance:

let balance = sdk.substrate()
    .get_balance("5GrwvaEF...")
    .await?;

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Additional Resources

Technical Documentation

• Typed Metadata - Type-safe runtime interaction
• Metadata Generation - Generate chain metadata
• Ecosystem Integration - Integrate with tools

Research & Advanced Topics

• Research Initiatives - Ongoing research
• Architecture - System design
• Performance - Optimization guides

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Tips & Tricks

Pro Tips:

• Use typed metadata for production deployments
• Enable connection pooling for better performance
• Set appropriate timeouts for long-running operations
• Never commit private keys or mnemonics
• Write tests for all cross-chain interactions

Common Pitfalls:

• Not handling chain-specific errors
• Assuming synchronous operations
• Ignoring gas/fee estimation
• Using example addresses in production

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Quick Links

Resource	Link
Main Repository	github.com/kh3rld/apexsdk
Issues	Report a bug
Examples	Browse examples
API Docs	API Reference
CLI Guide	Command-line tools

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