Skip to main content
This section covers the example contracts in example-contracts/. Each is a self-contained example that builds on concepts introduced in previous ones, progressing from a minimal contract to production-grade DeFi applications. The examples demonstrate how to develop blockchain smart contracts with seamless Rust-like testing and rapid feedback in a local development environment.

​
Suggested Learning Order

  1. hello-world → Minimal contract structure, basic functions
  2. token → Map-based ledger, Integer type, error handling
  3. shared-account → Nested Maps, authorization patterns
  4. proxy → Fallback function, delegation patterns
  5. pool → DeFi math, liquidity pools
  6. amm → Multi-pool AMM, production patterns

​
Example Contracts

​
hello-world

Minimal contract demonstrating basic contract structure, view functions, and simple state management. View Example →

​
token (59 lines)

Fungible token with Map-based ledger, arbitrary precision Integer arithmetic, balance transfers, and error handling for insufficient funds. View Example →

​
shared-account

Multi-tenant account management with two-level nested Maps, authorization patterns (owner and tenants), helper functions for access control, and contract receiving tokens via contract_signer(). View Example →

​
proxy

Generic contract delegation using the fallback function, FallContext, and foreign::call for dynamic forwarding. Demonstrates proxy/upgrade patterns. View Example →

​
pool (200+ lines)

Single liquidity pool implementation with constant product AMM math, LP token management, swap calculations, and slippage protection using Integer arithmetic. View Example →

​
amm (350+ lines)

Multi-pool automated market maker managing multiple token pairs with Map of Pool structs, dynamic token handling, pool creation, and production-grade validation logic. View Example →

​
Project Structure

Each contract directory contains:
  • contract/ - Rust code (src/lib.rs), WIT interface (wit/contract.wit), and wit/deps/ (symlink to built-in types)
  • test/ - Tests (src/lib.rs), build.rs (compiles, optimizes, compresses contract), and dependencies
  • Root Cargo.toml - Workspace configuration

​
Running Examples

To test any example contract: 
cd example-contracts/token  # or any other example
cargo test
Tests use the Kontor runtime for simulation, loading contract bytes from target/ after compilation. This provides fast iteration like standard Rust development. Each example assumes familiarity with prior ones, focusing on new concepts.

​
Finding the Code

All example contracts are in the repository under example-contracts/: 
example-contracts/
├── crypto/
├── token/
├── arith/
├── fib/
├── proxy/
├── shared-account/
├── pool/
└── amm/