Token Swap Program on Solana

A decentralized token swap program built on Solana using the Anchor framework. This program implements a simple automated market maker (AMM) with constant product formula for token swapping.

Features

• Pool Initialization: Create liquidity pools for any SPL token pair
• Add Liquidity: Deposit tokens into existing pools
• Token Swapping: Swap between tokens using constant product formula (x × y = k)
• Slippage Protection: Minimum output amount protection for swaps

Prerequisites

Before you begin, ensure you have the following installed:

• Rust (latest stable version)
• Solana CLI (v1.14.0 or higher)
• Anchor CLI (v0.31.1)
• Node.js (v16 or higher)
• Yarn or npm

Installation

1. Clone the repository:

   git clone https://github.com/Hemanthghs/token-swap
   cd token-swap

2. Install dependencies:

   yarn install
   # or
   npm install

Configuration

1. Set up Solana CLI for local development:

   # Set to localhost for local testing
   solana config set --url localhost
   
   # Generate a new keypair (if you don't have one)
   solana-keygen new

2. Configure Anchor:

   # Check your wallet address
   solana address
   
   # Update Anchor.toml with your program ID and wallet
   anchor keys list

Building the Program

1. Build the program:

   anchor build

2. Get the program ID:

   anchor keys list

3. Update the program ID in your code: (Important!)

   • Update declare_id!() in programs/swap-2/src/lib.rs
   • Update Anchor.toml with the correct program ID

4. Rebuild after updating program ID:

   anchor build

Deployment

Deploy to Local Testnet

1. Start the local Solana test validator:

   # Start local validator in a new terminal window
   solana-test-validator

   Keep this terminal open - the validator needs to run continuously.

2. In a new terminal, configure for localhost:

   solana config set --url localhost
   
   # Check that you have SOL (local validator provides test SOL automatically)
   solana balance

3. Deploy the program to local testnet:

   anchor deploy

4. Verify deployment:

   solana program show <PROGRAM_ID>

Client Usage

Setup Client for Local Testing

1. Deploy your program (if not already deployed):

   # In another terminal
   anchor deploy

2. Compile TypeScript:

   npx tsc

3. Run the client:

   node app/client.js

Client Configuration

Make sure your client connects to the local cluster:

// In your client code
import * as anchor from "@coral-xyz/anchor";

// Connect to local cluster
const connection = new anchor.web3.Connection("http://localhost:8899", "confirmed");
const provider = new anchor.AnchorProvider(connection, wallet, {});
anchor.setProvider(provider);

Program Instructions

1. Initialize Pool

Creates a new liquidity pool for a token pair.

Parameters:

• mint_a: First token mint
• mint_b: Second token mint

2. Add Liquidity

Adds tokens to an existing pool.

Parameters:

• amount_a: Amount of token A to add
• amount_b: Amount of token B to add

3. Swap

Swaps tokens using the constant product formula.

Parameters:

• amount_in: Amount of input tokens
• minimum_amount_out: Minimum acceptable output amount
• a_to_b: Direction of swap (true for A→B, false for B→A)

Account Structure

Pool Account

• authority: Pool creator's public key
• mint_a: First token mint address
• mint_b: Second token mint address
• bump: PDA bump seed

Resources

• Anchor Documentation
• Solana Documentation
• SPL Token Documentation
• Solana Cookbook